It is a violation of their terms of service.
There are plenty of good reasons to not use Anthropic's services. If you don't like their terms of service, do stop using them! I personally think Anthropic's increasingly successful attempts at regulatory capture are even more distasteful.
Oh Anthropic has shown their ugliness in more ways than one I agree. You have to have to done some pretty heinous shit for openAI to look good in comparison.