In general it is going to be impossible to block content. We need to charge for bytes or something like that. But that produces other problems which could be worse
It contained IPFS url with a login form sending data to some hacked site so this is already a standard practice.
It is also a bit amusing when you host your own mailserver for years.
I read that 25 year ago as a suggested solution to email spam, and it's many times less feasible today than it was back then.
There will be occasional false positives and some people would complain, but most IPFS gateway operators would just choose the top blocklist for simplicity.