Sounds like it's an extension API thing, where addons on Manifest V2 won't be supported for much longer. So this is less of a case of targeting uBlock so much as the usual run of older addon-death.

Not that I'm a fan of that shit at all due to the sheer inconvenience, but it's more of a technical and backwards compatibility problem than a Google-agenda kind of problem.

Granted, it's possible Google could make it less of a hassle with regards to the backwards compatibility and/or make it easier for addon developers to convert over to the newer API, but I'm not familiar enough with the specifics to be sure.