The fact that you put online (e.g. in an online shop or, heck, even for free on your website) doesn’t imply anyone can use it for anything they please.
For example an mp3 on a indie musician website for making people know their music, doesn’t mean people can start making CD out of it and selling them
You may say that piracy exists but it is illegal and AI training is pretty much for profit piracy (using something outside the intended scope defined by the author for profit)