1. Learn to walk right by the parents after the game and not say a word to them. You made a huge mistake by engaging them in conversation. As you learned they have so many positive things to say to you following a game.
2. I'm amazed that you think that you can get hired at the college level without any HS officiating experience. Perhaps that is the way that it works where you are. If so, good luck to you.
3. I would still recommend that you get HS certified.
4. If you are doing the rec leagues for the money, then be prepared to deal with the garbage that comes with the dough. My experience with rec leagues is that is what you are getting paid for.
5. Lastly, at 24 you are still very young. I would guess that is why the parents and kids think that they are able to address you like that. Perhaps they still see you as a youth. You will probably find that when you get some gray hairs, you will be treated differently, especially by the adults.