I appreciate that you yourself consider it a small thing that wouldn’t wind you up. But in all honesty, I have to say that’s hardly a great benchmark for how one should behave when using public transport / facilities.

I’m guessing that most of us are of the view that it’s important to consider the feelings and likely perspective of others in life rather than just one’s own.

There are people in First class lounges (or indeed onboard aircraft) who put their bare feet on other seats / tables adjacent to them, or across the length of a sofa. Such people would not be ‘wound up’ by the sight of others doing the same ; and hence they find it “acceptable” to do so themselves.

Anyway ..... as you say .... you’re “really not worried” .