AdNauseam is silently clicking ads. This directly costs Google money. Google happens to control the extension web store for their own browser. Removing it from the store really isn't that bad. Uninstalling it from existing browsers as malware? A little more malicious, but I would still consider it self defense.
There is even a method to install it directly[1] which AFAIK Google has not blocked.
Granted, if Google were not both running the browser and the ad network, these actions probably wouldn't have been taken. But the whole attitude that this is some sort of tyrannical thing is a little over the top.
1. https://github.com/dhowe/AdNauseam/wiki/Install-AdNauseam-on...
I agree that Google should probably remove browser extensions that are convincingly designed to facilitate actual fraud. I'd also be on board with Google removing a browser extension that was designed by a site operator to produce artificial clicks on ads on that particular site, since now there's someone involved who probably signed a thing saying they won't produce artificial clicks.
But my point with my examples was that you can harm someone's bottom line without it being fraud or otherwise illegal, so it doesn't just follow that if you harm someone's business, you're doing the equivalent of a DoS or smashing up their merchandise.