It's because there's websites out there that will entirely break, and for really dumb fucking reasons. I've seen some sites not even load due to google tag manager being blocked. Most of the time it's a signal to me that I don't want to have anything to do with that domain.

However, if this was at work, that would be a call to IT. Multiply that by potentially hundreds of calls on the regular, and that could get really expensive.

The better solution here I think, is to default the browser install with uBlock Origin already there. Then allow the user the power to toggle the addon to their own liking. Then last, train your employees to know what the addon is, and how to use it.

Then it's the best of both worlds: websites aren't necessarily breaking for all users, ads are absent as a default state, and users are empowered to control their own experience. (And yes there's still going to be Jims and Karens calling for support, but they're going to regardless, those types will always find a reason.)