Not a native speaker, but for me "giving a shit" doesn't sound like you really care for something. Ok, it's (maybe) better than "not giving a shit", which is nothing at all, but it's not much more than the bare minimum...
He's using it in an ironic[1] sense to mean that they really do care. This is similar to BBEdit's tagline[2], "it doesn't suck," which, read literally, doesn't mean it's good.
[1]: contrasting with expectations and norms
I think maybe ‘not giving a shit’ existed as a turn of phrase first, and ‘giving a shit’ is sometimes used (incorrectly in the grammatical sense, but ok in the colloquial sense) as the complete negation/opposite.