I wouldn’t because the data they offer are (among other) mine. When I contributed to SO I did not intend on doing so with a way for the data to be used in a model training. I did it with a license which specifically requires my work to be mentioned when used. And I still want that. Will AI regurgitate its code with the mentions of its sources? I don’t think so… Now I won’t contribute anymore but I can’t really remove what I already contributed, can I?