"Don't yuck my yum", is a phrase that essentially reminds us of our differing opinions, likes, beliefs, etc, and to not call them wrong or distasteful. What is "yummy" to me doesn't mean you have to "yuck" it.
Does this make sense?
Think about it this way.
What is your favorite flavor of ice cream?
If I were to say, cotton candy, someone might say, "YUCK! that's disgusting, how could you even like that flavor? It is so nasty. What kind of person eats cotton candy flavored ice cream?"
Do you see how that "yuck" unfolded?
This applies to EVERYTHING
One of the greatest aspects of life are our differences. It is what helps create and expand our perspective. Imagine if we all had the same "yum". Everyone would be the same, our perspectives would be incredibly limited. What fun is that?
So instead of yucking on someones yum, understand that what is yummy for them may not be what is yummy for you and that is perfectly fine. Further, there is no need to attack the other for having a yum that doesn't align with your yum.
Maybe instead, we can be curious...
"Why do you like cotton candy flavored ice cream?"
Through this inquisitiveness, you might discover that this person actually has an incredibly moving story where when they younger, they used to go down to the pier with their mother every weekend and walk around eating cotton candy flavored ice cream, telling silly jokes, and riding bikes into the sunset. And since then, their mother has passed on and cotton candy flavored ice cream is tied to beautiful and fond memories of their mother.
You see, we never will understand the full story if we YUCK someones YUM.