A person that I know has equipped a lot of routes at Skaha has had this same problem of hangar theft and route chopping. He tried the standard Petzl type glue ins but you can turn them out with a long bar. His expensive solution was a glue in "U" where the two legs of the "U" were glued into the rock (Check out the anchors on "Churning in the Wake" at Smith Rock). You can't turn this anchor and you have to hack saw the two legs to get it out of the rock.
His cheap solution was to purchase a box of stainless steel wedge anchors. He then boiled them in water till the oil was no longer coating the surface of the stainless steel. He then placed them into the rock, and used the heavy duty lock tight on the nut. When the route terrorist arrives with his wratchet wrench, the bolt will only spin, (the nut and shaft as one, spinning inside the cone) when he/she tries to remove the hangar. Of course you can hack saw this set up too but its going to be difficult (Knuckle busting hopefully).
I've climbed at Vantage and find it to be some of the best moderate sport climbing in the Northwest. It would be heroic for someone to step up and glue in the bolts or somehow remedy the situation.