It's actually a narrative they push, that it's good for shareholders. If you look closely, it's mostly not. They issue as much as they buy back. Basically, what appears to be done for shareholders is actually going to exec or employee compensation.

They buy back with one hand yet issue more shares on the other. If you look at the amounts, it's a wash. The only big tech company that actually buys back and actually minimizes the outstanding shares, thus increasing the share price for shareholders is Apple.