But, for a person with autism, behaving in this way is practically impossible. I wouldn't even know where to begin and how.

From my perspective, even the US cultural norm is way too taarof. It's normal for Americans to offer things for politeness, with no intention to follow up and the interlocutor is also expected to understand the offer isn't genuine. So a phrase like "we should grab lunch" can be said without being an actual invitation for lunch. And then there's the whole aspect of avoiding criticism or saying no. "I don't think that's a good idea" in the US is more likely to mean "no, we're not doing that" than "I don't think that's a good idea so you need to convince me more if you want to do that".

As someone who also struggles to decode situations where people's actual, implicit meaning runs contrary to the explicit meaning of the words, American norms of indirectness are already a headache. Persian or Arab communication is much more indirect and that sounds like a nightmare to me.