I've never heard this expression before, but I think this expression works against you here.
Many cities have a problem with people putting gum on the sidewalks. Some cities have banned chewing gum to combat this. This is similar to cloudflare banning questionable clients.
More on topic, I understand the view point here, but cloudflare is better than the way things used to be. With the privacy pass extension, visit sites with the tor browser is pretty painless. It used to be all too common for sites to just outright ban all tor traffic.
How is this an "externality" of cloudflare's service? If anything, it is an "externality" of the server hosts.
But if we take a step back it's clear that Cloudflare is the entity here that can have the biggest impact. Spammers and customers are diffuse, Cloudflare isn't. How much of the blame they deserve, I don't really care, but theres a problem, they're in the best position to act, so they have a responsibility to. In my opinion, that's the best mindset for solving problems.
This is, to me, a bizarre notion. You're imposing some sort of moral edict upon cloudflare for providing an opt-in service to web hosts.
> they're in the best position to act
They have, and they decided that certain traffic requires additional consideration to distinguish from bad actors. Your refusal to cooperate is entirely on you.
Just because you don't like their solution doesn't mean that there is a better one. If you have better ideas, I'm sure they're all ears, as less intrusive is generally cheaper to implement.