Lying about the scale of thwarted attacks by others is the counter argument
A) everyone inflates-- in which case, you want to be with the entity with the biggest pipes. Also, of course, we have reasonable estimates about how much traffic everyone can exchange.
B) non-CF players downplay DDoS-- this isn't going to work either.
You need an entity with peering, pipes, and request rates big enough in the right places.
Cloudflare has a ton of infrastructure, and this just makes them intrinsically more robust to the biggest attacks. It's in their interest, therefore, to make people believe there's a lot of really big attacks.
But this complexity likely works against your claim that there are reliable estimates, meaning that it's easier for everyone else to A) inflate their own capacities and argue that B) CF shouldn't be trusted in their assessment as it's inflated.
And I've already addressed your last point, so alternatively: if the biggest attacks are 1 bps of traffic, it doesn't matter that you have a ton of infrastructure because anyone can handle a byte. The lie has to exceed "capacities" of others for it to matter.
I think since we know CloudFlare has the biggest scale, we know that CloudFlare has the biggest capacity, with a higher baseline request rate and traffic exchanged than anyone else: definitely globally, and almost everywhere locally.
> And I've already addressed your last point, so alternatively: if the biggest attacks are 1 bps of traffic, it doesn't matter that you have a ton of infrastructure because anyone can handle a byte.
Which is why Cloudflare has an incentive to make DDoS attacks sound bigger.