Bingo. It’s that opinions are subjective, and therefore cannot be proven wrong…which for idiots translates to “one opinion is just as good as another”…and in turn, “all opinions are equal”. Plus it certainly helps when from a very young age everyone is told “everyone is entitled to their opinion.” Things like this are so easily stretched so far beyond their original meaning that they are used to justify essentially anything.
Here’s a great video highlighting clips from an interview with Thomas Sowell where he speaks to this same phenomenon. (The relevant part starts at 1:06 and goes to about 2:12)
(The full interview can be found here).
Bingo. I went a bit into this here. Never underestimate the power of indoctrination.