Stock buybacks used to be illegal. It's a loophole way of paying employees at a lower tax rate than salary. HBR discusses some downsides of buybacks: https://hbr.org/2020/01/why-stock-buybacks-are-dangerous-for...
Buybacks are just a more tax-efficient way to issue dividends to shareholders (dividend issuance is a taxable event and at short-term rates, buybacks raise the stock price and those gains aren't taxable until you sell, at which point it may be long-term cap gains). It's reasonable to be upset about the fact that this is arguably a tax dodge! But all of the other criticism of buybacks apply equally to dividends which…
I don't know what planet you're living on, where nobody's ever been upset about dividends.