Let me say this about that:
On Saturday night I had about 20 people in my house. Friends. Seven years ago I knew none of those people (apart from my wife). I met all of them at game stores, GenCon or the local ENWorld gathering we host called NC Game Day. Strangers who I gamed with the first time we met.
They were standing in my house on Saturday night, eating pizza (and corndogs! Corndogs are mandatory!), drinking beer and sharing game stories from the day's events. Why am I blessed to have such a wealth of nice people around me? Because I treated them as friends from the moment I met them. That's how I treat people I meet at game stores, GenCon and the like, right up until I'm given a good reason to do otherwise.
One more reason that I see little profit in brushing off those who ask a reasonable question of me as the GM.
20 alcohol siphoning litterbugs in your house? I would say cursed rather than blessed, but whatever floats you boat.
But you see you point to what I am talking about though. Why only 20 after 7 years with of all that? Is that all that showed up over those 7 years?
Your data really leaves too many questions to be of anything but more anecdote.
Why weren't all the rest there? Even if you were discussing thing, a key point that makes Obryn's post moot, is that we are all here in this thread because we WANT to discuss things. Take the answer I gave that you responding to as "good reasons" someone else hearing those simple reason could have had great fun playing an assassin and a strong liking to them. Had I said I don't like them, they may have asked why not, and gotten that as the answer. Then due to their affiliation with them or strong feelings about them, and argument erupts because somehow my dislike has hurt their past experience and potential future experience with assassins. In this case not giving a reason would have been better than giving it. An ounce of prevention versus a pound of pain....
As has been shown by others some people can get quite attached that a reason for one not liking something or doing it a different way, somehow instantly offends someone who does like it. It only gets worse when personal reasons are brought into it.
I don't know what kind of people you meet at NC State at your little things, but it had never interested me as it is a phony as other things claiming something that is not representative of the whole as far as I am concerned, but odds are you don't have every type of player attending because of lower attendance based on reasons such as Mace and StellarCon. Both of which will have people that are not very agreeable at them, at ALL game tables and wondering around the booths.
The many different people that would come into a game store or open game club as opposed to one held in places like a college, that seems and sometimes is, an event for those attending/enrolled there, are vastly different.
Don't even get me started talking about people from one specific store that was about as elitist as you could get as well snobbish.
So your weekend party didn't have everyone, couldnt have, from your events. There had to be a reason other than how many the house would hold as to why some didn't attend your house party.
Take the guy who left a game and never heard from again but passed on the street in the "walk away" thread. Different people are different. Some non confrontational and just walk away, other raring for a fight.
So someone saying "don't like it", might just also be one of those non confrontational people rather than have some DM superiority complex. Likewise some you invited might not have RSVP'd just so they didn't have to give a reason for not attending your get together.
As such simple questioning of anothers likes or dislikes is viewed by many as just plain rude....to bring this all back on topic.