Copyright infringement is still a viable angle against scraping. Who owns the right and thereby has standing is typically the issue. Thus, a dmca notice would have to be specific as to what was accessed / copied and those specific items would need to be copyrights held by the person who sends the notice (or on whose behalf the notice is sent). Who owns the rights is often defined by the ToS, for example twitter's tos states that the users owns the rights in their posts, Twitter just holds a perpetual, universal license to republish.

As a counter example, I have scraped sites myself, but when I have, I've targeted specific files in which the operator has no copyright, e.g. vgm files from various video games, though someone else may well hold the rights. Nonetheless, the operator would not have standing.

It's also possible that it may constitute a technical breach of contract, at least in California, if ToS limits the reasons for access and/or prohibits scraping.