A friend of mine says they don’t wanna “yuck my yum” whenever they’re about to trash something I like and it infuriates me, mildly

The part that's infuriating isn't the phrase. Its a good phrase when used correctly. It's annoying that your friend is explicitly hating on your personal opinion after stating they want to respect your difference of opinion.

People have different opinions. One person's "ew" is a other person's "oooh." So never yuck someone else's yum.