Which then brings up a question. If there are "specific ways" the genre deviates from reality, we can ask: Why those ways, and not others?
If we have a stack of thing that are all "realistic", and we discard three-quarters of them, the differentiator between what we keep and what we throw away is not "realism". So, the reason we keep death in is not actually realism. There's some other reason we keep it, and throw away the other realistic things.
The question is then what is that reason?
Realism. Realism is the reason or at the very least one of the reasons.
Realism isn't all or nothing. It's not formless unknowable void or absolute mirrors reality exactly. It's a spectrum. And our preferences can fall at different points on that spectrum depending on what we are discussing.
The percentages I'm giving are completely arbitrary to illustrate my point. The game has many different components to it and so combat can be 60% realistic, weapons and armor 75% realistic, the world(has atmosphere, land, water, etc.) 78% realistic, and races 50% realistic.
If I look at those numbers and my preferences for those categories are at least 50% for combat, at least 65% for weapons and armor, at least 84% for the world, and at least 65% for races, I will have issues with the last two categories, but not the first two. And my reasons are realism.
That's not to say that there can't be or aren't other reasons, but just that when someone says realism we can't just discount it and start looking for some other reason(s). We aren't going to have those exact percentages to go off of, but I can look at something and say that it is or isn't realistic enough for me.
And, by the way, it is a crummy accusation - I mostly run games. Death is the least interesting complication for PCs, but is it also the simplest and easiest for the GM to implement! So, if I was doing what was most convenient for ME, then I'd be eliminating a whole lot of other things before I avoided death as a consequence.
Death doesn't have to be the most interesting. For me(and a lot of other folks going by the posts), permanent death just has to be a possibility. It doesn't have too happen every fight or even every campaign, but we need to know that it is a possibility or none of the other complications for losing a fight mean much.
For me combat is going to be ho hum boring if I know that if I lose all that will happen is the mission fails, or we get captured, or something. Those other things only really hold interest for me if the ultimate failure is one of the possibilities.