The intent is that collateral damage from such actions is so enormous that they become unthinkable. "We'll just block all of Cloudflare's IPs" is like "We'll just ban all Chinese products". OK, so now your economy is in ruins, what next?
China's great firewall for example degrades access to some popular web sites, but it doesn't do a lot of IP blackholing because that hurts China more than they'd like.
They don't have to block all of Cloudflare's IPs. First they block 1.1.1.1 so that DoH doesn't work, then they look at" 'nown bad' domains and see to what they resolve to and start with those.
If there's collateral damage to some other sites, then depending on the 'importance' of that they want to block--oh well.
China's great firewall for example degrades access to some popular web sites, but it doesn't do a lot of IP blackholing because that hurts China more than they'd like.