So I'm almost at the end of my game now. Up on the dam, me and Grandma making short work of the Legion. Then Daisy flies in the Virtibird, and my Enclave buddies get out : and immediately start shooting at me! Seriously, I had to make with Annabell just to get off the dam. Why did they fire on me, weren't they supposed to be helping me? I don't get it. Is it a faction thing? (I'm anti-NCR and anti-Legion).

Where are the Enclave at? I havent found them.

Technically the Enclave were there to support the NCR, not you. So if you take the Yes Man/Mr. House route, they'll turn hostile. Same for any other faction that you made support the NCR.(BoS/Kahns). You can keep the NCR and their allies off your backs by passing a speech check before the main control room in Hoover Dam.

ah yeah thanks, that makes sense. I did go into the control room all guns blazing.