Subscribing is one of those things in youtube that actually don't piss me off. I mean, 1 button, and if in the future that youtuber puts up a video you might actually like, you can watch it. It's useful, yet not a super obligation. Sorry this guy pulled the stunt he did, though.
Anyway, don't get me started on the commenters. Youtube has some of the most vile, brain-dead people on the internet, in much alarmingly higher numbers than here.
Sounds odd. Sometimes a "next" button or two takes me to the subscription page even though I'm already subscribed. Was it an old video? He might have been trying to gain subscribers back then and been too lazy to unhide it.