Because after I'm finished with this current character I'm going to delete Dawnguard and only download it again when I'm absolutely ready to deal with the vampire menace. I don't want to have to deal with all that stuff when I'm trying to play through a guild storyline, then the civil war quest main quests and lesser quests. I don't see why they had to make the expansion pack such a hassle. I want to be able to deal with the vampires on my own terms.

1) It's an invasion themed expansion. Just be the Dovahkiin and handle your business. It's no worse than the random Dragon attacks, and they're easier to hit seeing as how they don't fly. Just punk them (or lets the city guards do it for you), and then tea-bag them and move on.

2) You can delete and re-download content as many times as you want. You've already paid for it, so it's tied to your GT now.

thanks for the answer! makes me happy but it was just seemed to me that they advertised it as a war between the hunters and the vampires no mention of them invading towns

Yeah, I'm with OP. The Dragon attacks were fine because they only really got guards involved. The vampire attacks always end up killing my favorite smith, or the nice beggar, something along those lines.