I'm actually older than my parents now Weem, so I reckon it don't matter much what they think anymore...
But more seriously, this question and idea seems interesting to me to consider not purely from the point of view of gaming in and of itself, but as a question of personality that perhaps illuminates what we choose to pursue as regards our entertainments and avocations. (Maybe even our vocations. I see a lot of correlation between the types of character classes I played in-game, as a general vocational idea-form - Paladins, Rangers, Wizards, Thieves - and what I ended up doing in real life: Priest, Detective, Scientist, Inventor, Writer, Vadder and Explorer.) I guess what I'm trying to say is that, as others have hinted at, I don't consider this so much a question about gaming as about personality and the nature of the individual.
With that in mind I'm gonna very briefly generalize here about my parents, and myself.
My father is/was (retired now) a sort of no-nonsense tool maker, designer, and engineer. In religion and politics he is conservative, except maybe on social issues. His main interests have always been physical, technical, athletic, etc. Practical, pragmatic, mechanical. He doesn't read much, except as regards technical journals, etc. Not very respectful of authority, and doesn't take orders well. He's big on charity work. Overall I'd call him extraverted, with introverted tendencies. Very set in his ways, stubborn, and stable.
My mother is/was (retired now) a more flighty, impractical, dreamy-eyed teacher and artist. In religion and politics she is very liberal (at least by my standards). Her interests have always been intellectual, mental, psychological. She is also practical in some things but I would call her impractical in many ways. She reads voraciously. Almost always respectful of authority. She's not big on charity work that I know of, but she is always protective and finically generous towards the family. Overall I'd call her introverted with extraverted tendencies. She likes a lot of novel things and is exploratory.
As for me many people I knew thought me a very unlikely candidate for anything like role play games. Others thought I was exactly cut out for stuff like D&D. One side of me is physical, athletic, wild-ass (I like danger), pragmatic, scientific (physics and biology and medicine mostly), extroverted, family and home-oriented, and I have worked as everything from a broker to a teacher to work in Intel and crime to a writer. Another side of me is very introverted, reads a great deal, I like to sketch and draw, I compose music, invent, breed big dogs, have an estate I'd really like to expand and covert into a ranch, plays wargames and role play games, enjoy hiking and camping out and exploring and vadding, studied to be a priest (I attend a small Baptist church out in the country, but I've gone back to studying to be a Greek Orthodox Priest, which I'll take up full time after I retire), and would very much like to go into a remote area away form everyone and live by myself for a year or two in a cabin, growing my own food and catching fish to eat. Then again I'd also like to spend a year wandering as a mendicant priest and missionary. And I wouldn't mind going to live at a remote archeological site either. (I suspect that after a few moths though I'd really start to miss my wife and kids and dogs.) I have basically four parts to my nature, Scientist/Adventurer/Detective, Family Man, Priest, and Monk. Though not necessarily in that order. The order or importance or primacy sorta varies and fluctuates with me. For instance the wife and I just celebrated the anniversary last night and I was totally wrapped up in that and enjoyed it immensely. (Wink, wink, nod, nod.) Today she and the kids went to a big church and missions function in another state and I got the whole house to myself for three days. So I'm gonna be working an old cold case (homicide), reading, exploring the woods and hiking, working on the land some if the weather will clear more, preparing some projects for my squadron, listening to a good lecture series on Thomas Aquinas, meditating and praying some (without any real distractions- the older I get the more I like and value the occasional solitude with God) and watching some boob tube (Super Hero Squad, which makes me laugh, and Caprica) for entertainment. I may also take my Great Dane-Saint Bernard out for a car ride. He likes that. I may go fishing a little too.
I see role playing as a part of my Scientist/Adventurer/Detective nature. With some Monk thrown in. In other words when I am swamped with other things and with other work role playing and gaming lets me pursue other parts of my nature in an imaginative fashion, or in my mind (Vadding of the Mind) when I don't have time to pursue those particular things for real. That's how I see gaming and that kinda thing, as an outgrowth of my other interests, rather than as a sort of disconnected or separate pursuit unto itself. It's a branch off a tree, so to speak.
And in some ways I think it reflects the sort of "personality fusion" I inherited from my parents. Or put another way, if I were different in nature I don't think I'd have had much interest in gaming. Strangely enough though D&D was the first role play game I played (it was the only one really around back then) and the one I most enjoyed, and still do, no matter the passage of time. Though I don't like all types or iterations of D&D any more than I like all kinds of games or RPGs, though I do like a wide variety of such games. The types of D&D games I like are pretty much like the types of other games I like and probably very closely reflect my nature, character, and personality, which is, as I've already said, sort of a personality fusion inherited from my parents. Along with those bits of personality and nature which are probably unique and peculiar to me as an individual.
To answer your question more specifically Weem I suspect that when I was a kid they read my playing and interest in such games as a natural aspect of part of my personality. As part of my nature. They never showed any real or strong interest in such things themselves, then again they never showed much interest in my chess playing, my wargames, my sword-fighting, my detective work, my biological experiments, my vadding, archaeology, or some of the other stuff I did either. It just wasn't in their nature.
They did show interest in stuff we had in common. Ball games and athletics and riding motorcycles and military matters and inventing and politics with my old man - philosophy discussions, art, music, writing, and reading with my mother. Family with both of em. That still holds pretty much true.
So I suspect, and this is just an hypothesis since we never really talk about this stuff, specifically because they have no real interest in it, that they look upon D&D and gaming in general as something peculiar to my nature and not theirs. But that they see it as a part of my personality.
Anywho, your question was interesting to consider. I'm gonna go listen to Aquinas now and catch up on some news and have lunch.
See ya.