I act. I receive about 5 takedown notices every day--the curse of running an open source DNS service (nip.io/sslip.io).
I've received over 1,000 takedown requests, but none came from Cloudflare or Google. Most of them come from Netcraft, Phishlabs, and doppel.com.
Are you getting takedown requests from people who don’t understand how DNS works, or… are they actually suggesting that your particular DNS server filter particular results?
They seem to invite it
This is literally false. They are one of the few hosts I have dealt with that actually does NOT do this. Their abuse reporting form even has check boxes that are optional to forward it to the underlying host and the owner. If you leave them unchecked they don't forward anything.
I don't know where you got your information from but it's quite literally the opposite of reality.
Now, whether or not they actually act on it depends on whether they are proxying the site or merely providing authoritative DNS. If they are just providing DNS they will continue to provide it and deny your report and I think that's stupid and frustrating. If they are proxying it they will put up a block page in front of it which is meh.