If the idea is that no one should be able to avoid complying with the GDPR, even if they decide they no longer want to do business with whomever it is exactly that's covered by it, then maybe the whole thing was a bad tradeoff. I'll grant that Google and Facebook might be acting in bad faith – hell, I'll just assume they are – but surely, for some not-necessarily-insignificant number of other entities, it should be perfectly fine if they decide that the costs of compliance exceed the corresponding benefits.
I mean, if you already have a android phone, NEST and use google everyday, would you want to delete your account? You can live without facebook, but google makes a lot of hardware that is quite useful.
Let see how it all ends :D
They either made it much worse after the author did the screenshots, or it was already extremely bad --that I could not find the link to open up that huge list of third parties.
I clicked on all the links I could find in that screen except for that huge 'I Agree' button.
I don't see any obvious reason why it would be. Yahoo! is being transparent about their data sub-processors, and letting you control how and with whom your data is shared. That's what GDPR says on the tin.
If there's an argument to be made, it's around the Principle of Data Minimization. But that's one of those subjective things. And, considering the size and scope of Yahoo!, it's not inconceivable they have legitimate (scare-quotes optional) uses for all those sub-processors.
If the legal basis is Consent, then you are correct, it must be opt-in rather than opt-out.
Which made me curious: could a service exist where citizens not covered by GDPR submit complaints, so that a GDPR-covered citizen could put the complaint in formally?
[1] Hidden opt-out is non-compliant, but Yahoo! went ahead and opted you in to a hundred different ad services automatically: http://gdprhallofshame.com/content/images/2018/05/ouch.jpg