You're actually doing drivers a good thing by doing your speeding in the left lane.
To us gearheads, the left lane is a sacred zone where hammering the throttle is mandatory. There it is frowned upon to drive slow and hold up traffic. Unfortunately, no amount of frowning will ever get all of the slow drivers out of the left lane. As this video from Vox states, most slow drivers don't even know that the left lane is reserved for us (aka people with a need for speed). This video highlights why going slow in the fast lane can be dangerous. We think it should be mandatory viewing at all driving schools, or at least all police departments.
Make sure to pass this on to any friends who abuse the left lane and help us eliminate the risk to us all.