“I have learnt to minimize the amount of friends I have who are vegetarian, religious or have extreme views about something. If I didn’t, I’d probably be so depressed from being lectured and told off all the time.”
If you have “friends” who are lecturing or preaching to you, I don’t think they’re really your friends. Even if they’re right and you’re very wrong. If someone continually brings a subject up even when they know you aren’t interested in talking about it, then I think they’re doing so more for their own purposes than yours.
I think it’s the case that almost everyone holds “extreme” views about some topic or other, but most don’t feel the need to bring them up. You singled out vegetarianism and religion, but anything can be a hot topic for someone.
Friends might need to do some sort of reality check or intervention on each other from time to time, and of course debate is good too. But there really is no need for frequent lecturing when amongst friends, I believe. It would have been much better if you had instead said, “I have learnt to disassociate myself from people who lecture me” rather than explicitly mentioning vegetarians, people who have faith, free software zealots, … by calling out these groups you unfortunately make yourself look like a troll who is lecturing.
You probably have more friends than you think who are religious or vegetarian, and you didn’t even know.