From my understanding scraping a public website you'd otherwise have access to is legal in the US. However, re-hosting that scrapped copyright content, particularly if it isn't transformative/fair-use (inc. only partial content) is very much either violates copyright, or best case is legally a gray area.

Google got dragged into court for exactly this, and they were summarizing/snipping, so they had a fair-use argument to make. This is a 1:1 reproduction of the content, so the legal arguments on fair-use would be harder to make I suspect.

I've personally used XCancel, and I really like it, but stepping back legally they're on shaky ground if Twitter decides to stop it.

-ish. A lot of legal issues are heavily based on the particular circumstances, so a general statement like "scraping is legal" summarizing the results of hiQ v LinkedIn is a gross oversimplification of the actual findings of said case.

In general, the cases where scraping has been found to be legal have largely turned on the basis of things like accessing the public parts of the website and attempting to minimize potential copyright violation. Here, these services are bypassing a login requirement and reproducing the scraped data in full--actions that have generally led to findings of illegality in the past.

It's not a slam-dunk case in either direction, and I think the result would come down more to the quality of the lawyers to craft their arguments. And SpaceX has the cash right now to afford the better lawyers.

Civil law is not centered around what is or is not legal. It is about resolving problems that fall outside of criminal law. It is a completely different set of procedures and approach to the law.

Sending a C&D ordering someone to stop doing a legal thing is also legal.