[SahAssar]

If you own the domain for a service used for free by many many websites and have encouraged people to use that service for free I think there is some responsibility to not transfer that to a bad actor.

If he simply made the DNS not resolve to a server anymore I'd be fine with it (and if giving people a warning a few months in advance would be great) but this is not inaction, this is selling trust. It's reasonable to have less than zero trust in anyone that would willingly sell my trust to an unknown third party for profit in this manner.

I think that people should have never used this service or used it with subresource integrity (which by design is not possible in this case), but that's not how it was pitched so now the owner has some responsibility if they want to maintain dignity and trust.