Re: Windows Server
If Cleanfeed can be defeated by not using an ISPs DNS servers, it's not fit for purpose. While it may be a useful way of detecting access to hosts with illegal content, it could be bypassed using a hosts file sent out-of-band.
Your argument for Google (or A.N.Other DoH provider) being prosecuted would seek compliance potentially with a prosecution as well, but I am not sure a DoH provider is breaking the current laws.
TL;DR: Cleanfeed can no longer rely on DNS for blocking content assuming it currently does as most (all?) ISPs use other methods to identify/block the traffic. The lack of DNS may result in more false positives but that's a small side effect given the nature of Cleanfeed.