Why wouldn't I?
Besides,
a) filtering to the front is usually legal where I'm from (but I do other things in traffic that aren't 100% legal)
b) the things I do on my bike may annoy/anger some people, but they endanger nobody (except possibly myself). Cars ignoring the laws frequently endanger other people, so it's not the same thing.

If it's a long line of cars, I'll filter forward(which I can legally do), some motorists dislike my action, but most motorists just keep it to themselves.
Though just yesterday, the driver at the front of a line made an intimidating swerve at me as we both started across the intersection on the green light, and I was stopped well forward enough to be in his line of sight, and I was in his sight for close to a minute while waiting for the light, so it was not like he didn't see me and my bright attire.