Again, how are you subsidizing me? Blanket statements are inadmissible in a debate. I pay the gas tax, excise tax, tax when I purchase a vehicle, tax on all maintenance, and a never-ending parade of yearly fees.
If you want to talk about subsidizing, how about the rest of the state is forced to subsidize the MBTA, even when it doesn't reach all of those towns? How about drivers are subsidizing bikers to be on the roads that are paid through the above taxes?
It's easy to frame an argument to suit your agenda. If you can afford to live right on the T, then you can afford to pay more and not make the people who can't afford to live there in the first place subsidize YOUR lifestyle.
At the end of the day, if you are making the argument that certain people should pay more, and you're not one of those people, then you can take a hike.