sense in your words im so blatantly ignorant would you like to give your thoughts on to how or y its not out on pc yet then please mister insightful im in need of your knowledge sense im so ignorant

I can do that.
1. Prep-work: In order to release a DLC you have to do prep-work, you have to line up server space allocations, talk with your distributors and create advertising. This work may have not been legally possible under the terms of the exclusivity contract with Microsoft, so may only have just begun.
2. 1.7: While Dawnguard may seem good to go because it "seems fine on the Xbox", it very probably isn't, there is most definitely numerous undocumented Dawnguard related fixes in 1.7. We also have to remember that without 1.7 Dawnguard WILL NOT work on PS3,
and if Bethesda has their hearts set on a PC + PS3 co-release (would save them some money) then that will be an issue too.
3. Certification: Also expect Sony to want to certify both Dawnguard and 1.7, this will cause delays too (unless the underlined of 2 isn't true, then it is just 1 that is important).
We are only in the first real week, and we've been told that information is coming this week.