The theory doesn't discount that, the question is why did we evolve to be that way. All the mysterious things the human brain do can be explained to a point but thinking about why we're wired that way is the ultimate mystery.
It is, I have like 10 people on Facebook who I haven't talked to in years, and barely talked to them then, who wish me happy birthday every year. I'm pretty sure they do it for everyone, and have some automated thing for it.
It's normal to say happy birthday to an acquaintance, or someone that you know online. But normally when someone says happy birthday, you say thank you. Or at the very least, you like their post.
No worries, it's easy to misinterpret or draw false conclusions from tweets. Im so used to people glorifying abusive characters that i sometimes jump to conclusions. Apologies.
With context it makes more sense. It just seemed a little weird to me; being kind and nice when "appropriate", sounds like someone altering their personality to seem a certain way to people, but actually just being a asshole in reality.