I can't speak for others, but I can say that for myself, mocking others helps me reinforce and practice my own frugality, and is free entertainment that I can share with those who share my disdain for overconsumption, hedonistic adaptation, and environmentally harmful waste. Because I came from a family that is financially responsible but still has a lot of wasteful spending and hedonistic adaptation, and am surrounded by coworkers and others who are spendthrifts and sometimes mock or challenge my choices, I find it to be a healthy break from their world.
It has also helped me develop the habit of judging all purchases, even my own. Back when I used to think like you (she can afford it, so what's the harm?), I was also justifying a lot of my own dumb purchases based on the same rationale.
So, it does add value to my life. In fact, it probably adds a lot more value than one of my other favorite forms of entertainment, which is literally watching talented people chase after a ball. Most forms of entertainment, after all, are rather silly.
If this kind of thing doesn't add value to your life, it is a pretty easy section to avoid. I can assure you that we know better than you about what adds value to our own lives, and don't need your help with that :).
On a somewhat related note, have you ever watched the movies "Broke" or "Queen of Versailles"? Or read about the history of royal families in Europe? It is quite common for very wealthy people to go broke spending money on dumb stuff. In fact, it is one of the most common ways very wealthy people go broke.