I don't understand the mental process that leads to the pattern

"I don't understand why other people would do X"

"Well, it can be because of Y, Z, or W."

"But I don't do/need/want any of those"

"..."

It's like it's a fundamental failure to understand that other minds are separate from yours and have different motives and preferences.

Okay, that’s fine for yourself, but as seen in this subthread, other people have different tastes, and needs.