Joining a critique group is an excellent way to develop your writing, but not because you get feedback. The biggest benefit of a critique group is the opportunity to develop your ability to analyze someone else's writing. Accepting feedback in silence is important, too, otherwise, you'll block yourself from learning.
The reason probably isn't the one you think. Yes, of course you join a critique group for the opportunity to have your work read and to get feedback on it. That's important. (A little later, I'll give some advice for receiving a critique.)
The greatest benefit of joining a critique group is the opportunity to read someone else's work and to give feedback on it. If you can figure out why someone's story isn't working, then you'll be able to apply that lesson to your own work. It's much harder to analyze why something works. Good writing and story telling is seamless, you can't really put your finger on it, it just works and it's awfully hard to learn lessons because you're too busy enjoying the story. You might pick up some good techniques, but figuring out what went wrong is going to be a zillion times more helpful.
Never argue or defend. Both will keep you from seeing that your hero isn't believable when he does X. He can still do X, you just need to work on why he does it.
Doing a good critique isn't easy. It's hard work and can take hours and hours. Hours you could spend writing your own story. Ask yourself if you want to be published. If the answer's yes, then do the critique and don't cheat anybody of your time and effort.