Because they are standards compliant and you aren't, and you are legally required to provide an unsubscribe service or whatever without undue barriers around it.
Everything else - no.
But if I am using standards and they have an ad blocker that blocks some of the functioning of my site, am I also required to test my site against that?
I'd include _everything_ important in the "yes" category. If I cannot access the customer panel to update settings or notify them of a bug that is affecting me because I'm using Firefox ("works for 95% of users"), they're just not keeping up their end of the contract.
Remember, 95% excludes everything but chromium/webkit-engines.
Every company decides which customers are worth going after.
Might still be a business decision, but it's like saying "we'll drop any emails that indicate a mail client other than apple mail/gmail/outlook".
It's not surprising that the strongest protections always happen on the unsubscribe links, but not on the subscribe-links. That just needs to be fined out of existence, just like "you can order with one click, but you need 50 clicks and a three-hour-conversation to cancel".
Just like other cases, I won’t accept that it’s “just lazy” on the part of big tech companies. They clearly know how to adjust their internal view/reputation of a domain once it starts being used for “misbehaviour” and spam such that they start blocking it.
Thus they could clearly start by not doing so-and, maybe, they’re “really touchy” about domains with no initial “internal score” such that if a new domain pops up and starts spamming people they catch it fast. Its not necessary to break open Internet protocols, though, unless they want the breakage.
One side of the argument is that Cloudflare places an undue burden. The other side of the argument is that without the CF protections, the service provider doesn't even have reason to believe the request is coming from a human being the law protects.
Where. It’s global internet we communicate via.