I don't care for the "it's optional" argument in general -- it's fair for users of an optional service to voice their opinion on how it could be better for them. As a developer that's something I want users to do. And I've learned to filter out tone when their tone could use a little work (or a lot, in OP's case.)
But in any case, you've failed to rebut the "it's optional" argument. None of your examples are related to OP's complaint about using the activity feed to keep up with friends.
Missing the sentence where the parent comment mentioned "using the activity feed to keep up with friends." Seems your rebut about my rebut failed, actually.
If someone wants to use a website, they should use the website. If they don't want to use the website (this includes the login mechanism) then they don't. If your belief that Facebook logins are a bad thing is widespread, people will stop only implementing Facebook logins because it's a bad business decision. Stop whining because the market doesn't agree with you.
> If someone wants to use a website, they should use the website.
…except when that website first make you use facebook.
> If your belief that Facebook logins are a bad thing is widespread, people will stop only implementing Facebook logins because it's a bad business decision.
These things are a slow process.
> Stop whining because the market doesn't agree with you.
Luckily, my "whining" (the part about the social logins that you could only argue against, my privacy points were bulletproof and spot-on) is backed up by evidence:
I agree, but it still comes back to the same problem. Relying on another site membership. What if SiteA uses Twitter to login because they don't want to make people have yet another login account, but I don't have a Twitter account... Great, so now I have to sign up at Twitter to sign up at SiteA... Making me have to have an account at a site I don't want to have an account at, just to have an account at a site I DO want to have an account at, just because Twitter is more popular.
That's as arbitrary as saying you must have pink hair to use my website. It's a dumb decision on the companies behalf, and for that reason not a legitimate concern with reputable companies.
Optional like the sites that have "sign in via facebook" and no other option?
Optional in that they track your every move from "like buttons" all over the web?
Or optional that they develop shadow profiles on users that aren't even users?
Which optional is it?