Everyone needs to validate their choices in life, by taking a stance opposed to the choice they discarded. Whether it's vocal or just internal, everyone has the opinion that anything they have rejected is necessarily inferior to the alternative they chose instead.
For example, someone who has decided not to drink alcohol for whatever reason will often look down (even in a small way) on people who choose to drink and get drunk - they will think they are "wasting money" or "damaging themselves" or "not really having fun" or whatever. This is only natural and human, and generally doesn't harm anyone, because it's just a personal opinion.
The problem arises when you attempt to either enforce this opinion on someone who doesn't share it (example above, telling other people not to drink and throwing a hissy fit when they do) or you start proselytizing at other people about how your choice is better than their choice, which seems to be the case in Straken's club.
To combat it, then I think you need to conduct a small breaching exercise - a way of breaking social norms in order to get across a sharp message.
Normally, when the situation you mention occurs, what do you do? I would imagine (since I assume you're a normal decent person) that you perhaps smile, nod, do your best to move the conversation onto other topics, refuse to engage, don't make eye contact or provocative statements, try to ignore them etc. This isn't working for you, since the problem seems to be getting worse and worse.
My suggestion would be to try something different. The next time someone goes off on one about 40k or GW, then move from wherever you are, and whatever you're doing (if you're playing then excuse yourself politely to your opponent) and walk over to the person and place yourself in front of them. Don't get all up in their face, a few steps away is fine. Make eye contact, hold it for the entire conversation, and say loudly, clearly and politely in the most firm manner you can get something along this line:
"Hi, I don't know if you've noticed, but I happen to enjoy playing 40k. When you rant about it like this, I feel that you are criticising me personally, because I have chosen to play this game. I appreciate you do not like the system or company, and that's your choice, but I would ask that you don't keep lashing on at it while I'm here. After all, if I bitched about how shit [their system] is every time you walked in the room, you'd get pretty sick of it too. Have some respect for other people, and please keep your opinions to yourself."
The key is to be strong, unhesitating and polite. Don't engage in debate, and especially don't argue or lose your temper. Simply say what you want to say and then walk back to your table and continue what you were doing - absolutely don't say this just before leaving the store (which will be seen unconsciously as weak). I'd say you've got something like an 90% chance of them apologising and stopping from doing it (for the next day or so at least) and a 10% chance of them raging at you, in which case you calmly look to the manager and say something like "I don't feel this person is able to respect the other people in this store", turn your back and walk away. Let them deal with it. In our society there is almost no-one at all who will stand in front of you, look you in the eye, and tell you to shut up - especially relative strangers. About the only people I can think of are the police and maybe teachers. By doing the same, you're taking the same mental space as those authority figures in their head, and so it's very likely that the conditioning we have (to do what we're told by authority) will be enough to get them to do what you tell them and shut the fuck up, even though you have no such authority in objective reality.
If that doesn't work (for whatever reason) then have a quiet word with the manager. Point out that you are being put off from attending (and mention anyone else you can think of who might be put off too - don't be afraid to speak out for every single other 40k player, they probably agree with you) and therefore spending less time in his store, less time playing his games, and spending less money. Odds are good that he'll stamp on it.
90% of people think they are above average.
Statistically Improbable. Psychologically Inevitable.
Last edited by Sethis; 01-26-14 at 11:05 PM.