Spain ISPs block CloudFlare IPs during La Liga matches.
Do you have a source for this claim?
TBH it is not ALL cloudFlare IPs but a significant quantity of sites using and not using CF CDNs. You cannot imagine what a pest that is even for legit users of legit collateral damage pages. CloudFlare is in the courts appealing/countering initial court allowance to blockade and ISPs are bound to comply to blackout requests. You can look at https://hayahora.futbol (traslation: is there soccer match now?) to see affected domains.
While I am not some reputable source per-se, I have some tailscale presence over there and can corroborate my exit nodes find cloudflare sites blanket blocked on weekends.
I remember hearing someone complain on HN of their site getting blocked because it shared an IP with an illegal soccer livestream. I can’t imagine they’re doing this to IP blocks owned by CDNs like Fastly, CloudFlare, or CloudFront though. Or are they? Does this regularly break most of the internet for UK customers?