Happy, I've not been active on this for a while because a) I had to drive a hundred miles to go pick up a guitar I bought on eBay, b) had an early morning, and c) don't have the time at the minute.
I'm still 100% backing his version of events though, based on the fact that 99.9% of what DM has said on this thread regarding the topic at hand has been well-established lore. Also, the fact that you were unaware of the Dragonborn Prophecy and the fact that Ulfric started those wheels in motion again goes to show that your knowledge on the game just isn't quite there. It's great to have an opinion, but you have to be able to back it up with lore and evidence. I understand that you feel like you have, but I don't think anyone else on the thread is convinced.
And yeah, me and DM have disagreed on points before and had a nerd-fest over it. He doesn't give in, and we've had to agree to disagree more than once. Neither of us have ever resorted to spewing abuse and insults to innocent bystanders, though. The site encourages well-sourced and polite debate, it's the fuel for a great discussion.