There is a good presentation from the CEO of Kongregate talking about this here: https://www.slideshare.net/emily_greer/dont-call-them-whales...
I share your moral intuitions about exploiting whales if whales are, in fact, little old ladies suffering from social isolation or teenagers with undiagnosed depression. But the F2P companies say that they've done the research and come to the conclusion that most of their whales are gainfully employed professionals.
That sounds... not intrinsically implausible to me? I enjoy video games, quite a bit. Games, books, and hating on Bitcoin are my hobbies, and hating on Bitcoin is cheap. I have probably sustained $100 a month on video games for ten years now, and that would frequently be concentrated on a single game for an extended while (e.g. LoL for 2 years), likely resulting in me easily hitting their whale lists.
I feel like if I'm a central example of a whale that it isn't unethical to sell me things that I like? It's not a material amount of money given my financial situation. It compares very favorably to the time commitment for my main hobby, which causes _much_ more friction than the money does. (The primary reason I don't play LoL anymore is an unpauseable 40 minute game doesn't play well with having young children.) Most external observers would categorize me under Either A Responsible Adult Or At Least Fakes It Decently Most Of The Time. Similarly well-adjusted people in my social class spend similar amounts of money on things which are not morally different than Evelynn skins, for example Hamilton tickets.