My son uses awesomesauce regularly in Facebook posts.

I've seen newspaper articles complaining about both manspreading and fatbergs. (And if I lived in a city, I would probably have heard them in everyday use.)

Grexit gets used a lot by Paul Krugman.

Fat-shaming is a pretty common complaint.

Bruh is one I'm not sure I've seen, but it's apparently a variant of bro.

Brexit, brants, hangry, and cakeage are the ones I suspect are specifically British.

So on the whole, I don't know why the list would be considered unexpected, except by someone who hasn't been paying attention.

might be from 'bru' a familiar form of broer an Afrikaans word meaning brother.

Wolf