This sort of thing is so self-sabotaging. The website already has your comment, and a license to use it. By deleting your stuff from the web you only ensure that the AI is definitely going to be the better resource to go to for answers.
I’m not sure about that… in Europe don’t you have the right to insist that a website no longer use your content?
Not when you’ve agreed to a terms of service that hands over ownership of your content to Stack Overflow, leaving you merely licensed to use your own content.
Also backups and deleted flags. Whatever comment you submitted is likely backed up already and even if you click the delete button you’re likely only just changing a flag.