I think that grammar checking is a perfectly valid way to use AI. Though I haven't tried it myself, yet. But I do know that using earlier grammar checking tools helped me to learn the rules easily. So I never felt that made me lazy.
I'm not sure why, but reading your post made me wonder if politicians have an Artificial Stupidity tool for their speech writing?
I'm pretty sure it's standard practice to dumb down speeches for the masses. Before AI this was probably done by professional propaganda wordsmiths. I once read a speech by 19th century frontiersman turned politician Davy Crockett. It was so complex, so elaborately convoluted, composed of run-on sentences addressing various ideas at the same time, that it was hard for me to imagine how he could even deliver it, let alone what impact it would have. Supposedly it was well received, but I'm certain it went over the heads of most potential voters.
I can imagine they do.I don't think it's a great time for writers of any kind!