Your question title says playing human, but the quote says playing humans. These are two very different things, and this is the source of your confusion.
Play human would mean 'pretend to be human; imitate a human' as you've suggested above. But that isn't what this example says. You should be able to find this meaning in dictionaries readily.
Play humans, on the other hand, means 'manipulate humans to get what they want'. This meaning is a little tricky to find in dictionaries since it's a bit slangy, and that's probably why it was put in quotes, but it's related to the meaning play (someone) for a fool which you should be able to find:
play someone for Treat someone as being of (a specified type).
‘don't imagine you can play me for a fool’
(Source: The Oxford Dictionary of English)
The slang version of the word can be used without a for-phrase as a complement.