Oh boy. The casual gamer table. Sorry if your table does not actually contain them. As well as the phrase itself, but it just happens to be the short phrase I use for what you've described.
Here's a thing. RPGs are big. Really, really big. Some of the biggest things out there. They can be just as big as basketball or working on cars or other really big, more mainstream pastimes. The problem, quite simply, is that if you are discovered to be a fan of tabletop RPGs, that almost automatically labels you as a NERD. (For some inexplicable reason, people who like video game RPGs do not suffer this same stigma). This is absolutely wrong. Vin Diesel - he of the I AM GROOT/Richard B. Riddick - is a D&D player! Matt Damon, too, if you believe that. And Judi Dench. JUDI DENCH, Dame of the British Empire.
You can absolutely be a nerd, be a stolid fan, and not be some quote-unquote asmthatic pimpled geek. From your description - and I am sorry if this offends anyone - they sound like the gay guys who are trying to desperately convince people that they are not gay. They're ashamed of what they are...which destroys their ability to cope.
And the fact that your GM seems to be stuck about a quarter century in the past doesn't help, either. There are lots
of good, exciting, new
RPGs out there that are worth owning...but if the guy leading the table is constantly worried about players trying to game the system, then either he's not all that trusting of his players - he looks at every player and all he sees is a potential munchkin, or he's the sort of narcissist that knows he
would take the opportunity to optimize/crunch a character in a hearbeat, and therefore everyone is just like him. It's a very flat perception of who players at a table can be...though given your players, I might see why.
Honestly, for me? The thing you're doing is the best thing that you can do to break the rut. Leave the group - that you are moving gives you an excellent reason to - and don't go back.
Your table is not a table. It is a collection of persons who are interested and yet not interested in RPGs who are led by a guy who is potentially narcissistic or paranoid.
Hey! Your table should totally try Paranoia!
No, but seriously. Get yourself out of there. Tables are more than just dice and books and character sheets and adventures. They're social gatherings, and the people who go to them need to be comfortable in their skins as players.