I think opt-outs are a bit backwards, ethically speaking. Instead of asking for permission, they take unless you tell them to no longer do it from now on.

I can imagine their models have been trained on a lot of websites before opt outs became a thing, and the models will probably incorporate that for forever.

But at least for websites there's an opt-out, even if only for the big AI companies. Open source code never even got that option ;).