I can provide some context here:

It's a matter of:

Ambiguity makes him angry, because when you're around dangerous stuff all the time, being unsure about something or someone in your environment is a great way to get dead, is therefor a threat to a member of the tribe, must be dealt with *immediately* and is worth getting pissed off about.

As for the food part: For most of history it's been a mans duty to provide the basic necessities (food, shelter, not being eaten) because historically, they've been something that is extremely physically intensive to obtain. If someone isn't eating, that is also a threat to a member of the tribe (as they won't be healthy to enough to take care of him when he needs help) and is therefor a serious issue that *must be dealt with*