It's not an obsession. The US has tremendous influence and power all over the world, so are naturally scrutinized. For example I very much doubt the President of Brasil would be who it is if Trump hadn't been elected before in the US. Although the US cannot be held responsible (i.e., "blamed") for the choices other societies chose to make, it has a tremendous observational value, almost predictive. For example, the first time I heard of excessive political correctedness issues was in relation to American universities. Fast-forward two or three years and the exact same issue is being debated here in relation to the Portuguese universities. To suggest that other countries should ignore the US because you "don't give two shits about them" either is a bit stupid. Your influence is far beyond economical and military, it is cultural too.
You are also the biggest western developed country in the world. And size matters in these things. I was just mentally thinking about all EU countries and I know the name of the head of state of every country more populous than Portugal (except Netherlands and Poland) and don't know the name of any of the smaller countries (apart from Hungary, who is well known for the worst reasons). You naturally pay attention to who is bigger.