Part of it comes down to actual prejudice, part of it people being a-holes (prejudiced or not) and part of it is people being oversensitive.
There have always been assholes and they will always be with us. Assholes make insensitive comments, because they are assholes.
I have a brother-in law who falls into his category. One of the biggest mistakes I ever made in a lifetime filled with mistakes was to go to work for him, a situation that lasted for around 4 years. He would often say or do things when reacting with our clients that would cause them to ask incredulously after he had gone, "why does he say/do things like that?" I would just look askance at the questioner who would then apologetically say, "I know, I know, because he's an asshole."
This is a perfectly acceptable answer and should close the matter.
Devolving to the point where the explanation becomes, "he is obviously a cisnormative, patriarchal, white privileged, microaggressor," makes me glad I am coming down the homestretch of my lifetime and will be dead before the world is smothered in this happy horseshit.
*MySmiley*
"Bustin' makes me feel good!"
Ghostbusters, by Ray Parker Jr.