(Not an expert on the US tax system as I'm a Brit, but it seems that the tax treatment of dividends depends on how long the stock is held, and can be taxed at income tax rates, while stock buybacks result in inflating the stock value which is always CGT. Not sure what the tax treatment is for institutional investors?)
NB that "returning money to the shareholders" is ultimately what companies are for, and we should completely expect them to do this because without it investors wouldn't invest in the first place. It's infinite zero-dividend growth that's weird (Amazon).