That's great if they're the only one at the light. In my case passing on the right would mean pulling into the oncoming lane (with tons of oncoming traffic) to get around the people who didn't pull to the right.

Someone did it to me again last night. I had no intention of filtering forward, but he saw me riding to the right and pulled halfway onto the shoulder. As I actually got close to the line, I pulled out and took the lane (left wheel track) as I usually do at that light. When he saw this, he moved back into line (he'd let a gap form in front of him).

I can only assume that people have gotten used to cyclists that break the law a lot. I have actually only even filtered forward maybe 4 or 5 times, as an experiment at this one intersection. I don't do it anymore.