I would suggest from a mental health and happiness perspective to avoid dwelling on why you believe your friend is acting the way they are. Their reasons are of

I would suggest from a mental health and happiness perspective to avoid dwelling on why you believe your friend is acting the way they are. Their reasons are often less dramatic than what your brain might come up with. But if you do feel like knowing their psychology would be important then I think talking to them would be the right thing to do. People rationalize passivity by telling themselves they don't want to be pushy/hurtful/creepy etc. You can always be nice about it or ease into the topic ("have you read this article about conversation I saw on HN?").