You’re arguing against two different points I’m making:
- most maps have a Stargazer “base”, and;
- I think the new map will be Stargazer HQ.
Those aren’t contradictory points at all.
As for why the predator would be there, we know that Stargazer has and is actively collecting predator tech and remains. More broadly speaking, we also know that the predators are drawn to conflict, so the two organisations going against each other in open combat would be reason enough.