In fairness to Google, it's not absurd in principle. Mozilla has dealt with this problem for years: when an extension slows the browser down, the user is more likely to blame the browser than the extension. But in this specific case of ad-blocking extensions, I have a hard time taking Google's justification seriously. Ad blockers speed up the browsing experience far more than whatever negligible processing time the filter process takes.

That's exactly what it is- taking the choice away from the user. There were other options they could have taken- such as warning a user when installing an extension that uses these APIs, or building out a new asynchronous API (like Firefox did).

Instead they choose to go with the option that screws over users but might make them more money.