People are weird about gasoline. They'll drive around looking for the cheapest option, to save 2 cents/gallon. Even with a huge tank, that's less than 50 cents of total savings.
So a grocery store can offer, say, 10¢ savings, and it only actually costs them like $1.50-$2.00 per customer. That's way less than other sales that are harder to advertise and don't bring in the same amount of business.
Ultimately the psychological benefit for the shopper is more than the financial cost to the store. The others societal costs don't come in to that equation.
"Corrupt" would almost certainly be a statement of opinion, so not actionable in the US. A lot more detail would be necessary for this to be defamation.
"Judge XXXX has taken millions in shadow bribes and has consistently ruled for the wishes of his/her benefactors. There has been a history of being reversed on appeal proving their bias. Also I watched them kick a puppy."
Then, obviously, these things would have to be false. Even then, the bar is pretty high. There are exceptions both ways on this, but as a general guideline, if the public knows a person's name (judge in a high profile case, for example) they are probably classified as a public figure. The rule there is one of "actual malice" which isn't exactly what it sounds like, but it's the highest bar for defamation cases.
The speaker would have to say something factually false, knowingly or with no regard for the truth. Giuliani, for one recent example, was found guilty of defaming the Georgia election workers, because he went into great detail about his false claims, and he was told repeatedly that thise claims were false, but he kept going.
Requiring a login would probably cut off a significant portion of their audience and ad revenue. Only Google analysts know for sure, but if the eyeballs lost to cutting off casual visitors (sent to YT from links or embeds, etc) are greater than the losses due to, frankly, a small portion of users who would just end up blocking ads in other ways, it's a net loss for Google.
It wasn't compromised. If you can't be tracked and cross referenced with all the other data that brokers have, your activities aren't worth anything to reddit and they don't care about that account.
