Yay. #ublock_origin restores #youtube usability.
Just as I'd *finally* gotten a broadband connection again, Youtube started acting up, first issuing threats and then refused to work with #adblock_plus at all.
But uBlock seems to work for now, no more threats or nastiness from Youtube.
Tell 'ya what, Google - let uploaders decide whether to enable or disable ads and I *might* turn off my adblocker (and only watch videos who's creators disabled ads of course... I still won't ever watch ads).