Play whoever you want, but that doesn't mean your teammates are wrong. They're wrong in flaming you, but the jist of what they're saying is true.
Sure, you might not like playing Tristana when she's OP. But you can't deny that in a close game, if you were to play Tristana (and you weren't complete shit with her) that you would of won the game as opposed to an Ezreal or Sivir. You can and will consistently win more games by picking stronger champions if you can play them close to the level of your "worse picks".
I'm sure you can jungle Jinx or support Ahri at a decent level. If you were to play jungle Lee/Panth or support Nami/Janna at an equal or even slightly less level than those champions, your team would have a better chance of winning just based on your picks. Whether you agree or not, the champions not only fulfil, but they excel at that role. Teemo can jungle, but he's not a jungler. You can have a 70% win rate with Teemo jungle, that doesn't mean it's a good or viable pick. And it certainly doesn't mean he's as good or better than a Warwick jungle.
If you're as good or even slightly worse at the meta picks than you are with the "troll" picks, you will see more success in your play. Not to mention you wont throw your team on tilt by your uncommon picks.
Now, I'm not saying don't play Ahri support because she isn't a meta pick. Play whoever you want, have fun. What I am saying is that if winning is your priority, you'll put yourself in the best situation to win and that if you're picking uncommon champions, whether you agree with your teammates or not, it is expected (and will) upset at least half of them. Ignore it and do your best.