This is to no one in particular.
Quite a few gamers (and geeks in general) are on the autism spectrum, me and most my family included. Being loud or having no social life just happens to be part of it for a lot of us. I have no social life other than gaming and a few cat related contacts. My husband is loud, and I'm sure a lot of people would consider him obnoxious, but he can't control the volume of his voice, he never could, despite years of vocal training. We have 2 players with tourette syndrome, one who constantly laughs or breaks out in song and one who keeps repeating what everyone else said over and over. My cousin who I get most of my published adventures from has a sneezing tick. Myself, I talk to myself a lot when I'm going through my notes or books and I guess that irritates some people as well. At least my husband tells me to shut up when I talk on the computer too much while preparing stuff. None of the mentioned reads body language well or uses it correctly.
I don't WANT to bother with people anymore after I have been mobbed out of all my former social groups who, no doubt, didn't want to bother with anyone not like them, or probably thought I was giving them a bad name. Society at large tends not to think about why someone is/does something differently. It doesn't need to as 'society' is always the majority. But this hurts a lot of people.
Yeah there are definitely players I wouldn't want to hang out with either (and bad hygiene definitely is one reason, including clothes smelling nicotine). But it just so happens that for plenty of spectrumites, gaming, whether RPGs or board/card games, happens to be the only opportunity or reason to meet people and, in the case of RPGs, be someone else for a while and forget a life usually full of misunderstandings and social confusion. In fact, RPGs often teach some of the social skills people have issues with.
Now I'm not saying anyone should play with people who constantly irritate them, after all it is your precious free time we talk about (and I have removed someone from my games in the past). But maybe stop and think next time you find someone can't control his voice, or has ticks, or seems to be overbearing in body language. Sometimes talking to them helps, too, as it is not always the case that they even have the slightest clue about what is wrong. And it's not like all people you game with need to be friends in the general sense.
On our table, at least, anyone is welcome who can be a team player and doesn't push his/her PC in the spotlight all the time and who follows the rules of the place we are gaming at.