Actually thinking about it, it might not be a moral panic thing. It could be that if people use midjourney for pornography, that will play a roll in its training that could screw up the searches for others. Its like using google search with safe search turned off; even a perfectly innocent search can still result in NSFW results. So they exclude the porn searching while the AI learns so that it doesn't pick up bad habits while its in the early stages of its training

Also the company might also not want their AI to get associated with porn. That's just not good for PR

You just don’t want to admit that corporations HATE unions and will do whatever it takes to prevent them from forming

It us illegal to fire someone for trying to form a union. That’s why companies will instead INVENT other reasons to fire them regardless of whether or not its true