Growing up in Oregon in the 70's and 80's a lot of my friends had moved up from California. I still don't get this reaction but I guess people always need to find a scapegoat. A lot people don't like change and clearly people feel emboldend to act like jerks now that civility is pretty clearly out. A bottom feeding media and total jerk spewing out constant hate from the White House probably leave people feeling like they can do crap like this.
BTW, in case anyone is interested there is
an informative series in the Oregonian on where the growth is happening.
Personally I think most of the changes in Portland are positive but then again I'm only there for a couple of weeks a year.