Well from what I can see, you are not able to afford skins in other games, so I'd wager that you are struggling financially in real life.

I empathize with that, but putting that on this situation is projecting one instance of opinion on money and wouldn't be fair criticism.

$15 to me and other people is nothing. To a person who is really struggling, that $15 could mean the difference between having food on the table... or none.

To someone with $50k in the bank, $100 to a streamer could mean nothing. While the streamer who got that donation would objectively really need it more than the person who donated it.

Of course, all people are different, so people's tastes with giving/recieving money will differ, but people will spend money purely because they like something. There isnt always a virtuous or future-oriented reason to spend money, whether it offends you, or not.