clearly people are buying humble bundles and gifting the keys separately, is this really allowed?

Yes. Gifting individual bundled Steam game keys is allowed on SteamGifts.

Yeah it's allowed, but you can only get cv up to 30$ with bundles then they're just giveaways that don't give cv.

There are limitations to the contribution value you can gain from bundled games, so it won't benefit them for long.

why are people mad about others giving away games?

I've given away 3 of the games i got in the humble bundle purely because i have them or wont play them, dont really care about the CV.

I gift away the games I don't want from the bundles myself and I think it's good we can do so. It's good though they've put a limit, as otherwise I can imagine many people would only buy bundles to boost the CV.

Yes there is a 30 dollar CV limit from bundle games. But did it ever occur to you that it might be nice to give away your spare bundle codes even if you're not getting any CV for it?

You should read the FAQ. It's linked at the bottom of the page and also here.

OMG! HOW HAS NO ONE REALIZED THIS IN TWO YEARS?!

i.e. I don't have an intention to play Shivah from Android 9 Bundle; if my friend doesn't want to as well, i'll open a giveaway for sure. Better than add to your account if you don't want to play, right?