The power struggle stuff I've definitely seen in my life... In my youth I traveled around and stayed in youth hostels. I was into "Illy" brand coffee at that time, and would take a metal tin of whole beans with me to grind for coffee every morning.

One morning I was in the shared kitchen and there was an older man who asked what I was doing... He was from another generation where "coffee" meant freeze-dried crystals, so my approach was novel to him. He asked why and I said I thought that the beans lock in the flavor, making for better coffee.

He clearly took this not in the spirit intended, which is "this is what I'm doing since you asked," but rather as "I think I'm better than you." When he made his coffee he sipped it visibly in front of me and said something like "mmm flavor is LOCKED IN!"

I didn't think much of it at the time other than an odd encounter, but since then I've met others in my life who have the same reaction; when you explain some practice or life preference that's different from theirs, they take it as an implicit declaration of your superiority, and feel the need to "defend" themselves.