[imoverclocked]

Because there is a social element to watching videos. Losing some percentage of users means they will also lose some percentage of shares from those users. Those users may also tell people not to share links to YouTube with them. YouTube is a dominant platform for certain content but everything they do to be less friendly is something another platform can do to gain market share.

[rileymat2]

But pushing users that you can't monetize with ads into another platform can sabotage the economics of that platform in the short term? If that's the case, it almost sounds like a "win".