There is an ecosystem of competing CDNs. Blocking any one CDN necessarily impacts all the sites hosted on that CDN. This is a function of being a webhost with multiple customers not being Cloudflare specifically.
Except that the problem here is that Cloudflare, specifically, is so widespread that blocking it is highly likely to block many very important things.
If the ecosystem were truly more competitive, it would be much more likely that, for instance, if you went to block the CDN serving one particular football piracy group, it would not block half your government websites at the same time.