When you signed up, you agreed you understood the line - which is whatever Anthropic decides the line is. Legally, the line hasn't changed at all, nor has your moral position relative to Anthropic. Don't like it, cancel, but it was always the deal.

This is, by the way, the same legal principle that the website you are posting on, right now, uses. Some uses are prohibited. Not every line need be explicit. You aren't allowed to smack talk Y Combinator or the moderators without possibly being banned for life, and you certainly do not have a legal case if they do.