My position is that this looks like a backdoor but there is no way to know for sure, and I stand by it. If you find it too nuanced that's ok.
In any case, no hard feelings were intended anywhere.
But that's what mostly what I was saying (granted, I got worked up at one point because the blind stereotyping puts a black mark on HN's reputation in my eyes) is that indeed the situation is ambiguous and both possibilities are [mostly] equally likely.