Spreadshirt to artists: We’re taking your designs for AI

I'm not even sure I understand the point of this supposed "feature". Isn't their business model mainly targeted at people who want to sell merch to their fanbase or their followers? In this case, I would imagine that most creators would want strong control over the final product in order to protect their "brand". This seems very different from stock photography / stock art, where creators knowingly relinquish (most) control over how their work is being used.