This is equivalent to "I know you are going to use our invitation service to invite people to a meeting of your local gang, so we have made the emails go out with a typo in the location and phone number field", which has the same sort of "wait, are you sure it is a gang? how do you define a gang? is the gang even doing something harmful today?" problem that comes with the term "phishing". While this is much better than them claiming to block "spam" (which I will claim has so nebulous of a definition as to be meaningless), this is still a slightly ambiguous classification of any given communication due to how it interacts with trademark law.
Regardless, now that they have shown that they are interested in modifying the behavior of their platform to stop "using the Cloudflare platform for evil" (a direct quote from their blog post), clearly they now also should be using similar techniques to stop people from sending email about drug paraphernalia, and they should stop people from sending email with hate speech, and they should stop sending email about terrorism. They also should, of course, stop people from sending email about software piracy, or sending email about services designed to undermine copyright like SciHub, or sending email advertising "obscene" pornography.
They have now shown both the ability to do this and an interest in doing this, which is exactly what they recently demonstrated with the Daily Stormer SNAFU, where they showed the ability and interest to block use of their service "for evil"; in that case, the people were "Nazis", which may or may not be more clear cut than "phishers", but the scenario is essentially the same... and they are now having to backpedal their actions in court as this is being used as evidence for why they should be responsible for blocking piracy on their platform. The reality is that once you show an ability and an interest in policing content, what kinds of content you are forced to police will be taken from you and given to the state.
https://torrentfreak.com/daily-stormer-termination-haunts-cl...
Cloudflare's decision today is going to be devastating not only for them, but for the Internet as a whole (as usual :/).