If you have no where to move to, (lanes clogged to the front and the sides), I can understand your reaction.
However, if there is room to safely move over, why not?
If you were doing 80 - 85 on I280 and came upon someone going 70 -75 in the same lane, you would want them to move over for you, wouldn't you?
I think there's a reasonable limit to what you can expect in the fast lane. People who are going 100 mph and expect everyone to get out of the way need to learn that they alone don't own the road.