Right, it’s not perfect but there’s no need for conspiracy theories (but they seem impossible to resist for lots of people when it comes to covid). I had an exposure to someone who tested positive a few weeks ago, and I got tested and since I was vaxxed and tested negative, I didnt need to quarantine any longer. A quick check of UK rules show that it’s similar there, i.e., if he was vaccinated he probably wouldn’t need to quarantine. But if it’s a suspected omicron exposure even if you are vaxxed you need to quarantine, so who knows.
edit: I was just trying to read the UK exposure quarantine rules, and it says that you need to have been vaccinated in the UK to avoid quarantine, so probably his vax status is irrelevant because it would have been done in the US. That seems like a strange rule.