Short Answer: I had a schedule conflict that meant I would have had to race down to the National Mall, then race back in time to make my other obligation.
Long Answer: The bishop was visiting my parish, and I would have gotten out of there around noon, metro would have taken until 1 and then I would have had to leave by 2:30 or 3 to get back to Greenbelt in time for my obligation. Also, I didn't have a huge interest in the march. Call me a cynic, but I felt that many people were using it as an excuse to come to DC and party, show up at the mall, shout for a while, then go home and pat themselves on the back thinking they did something good. Meanwhile, they will continue to do nothing to engage their own politicians about why equal rights are important.
Before anyone gets on me about this, understand that I do regularly speak out about equal rights to family, friends, and politicians alike, so this is not armchair activism by any means. Anyone who locally knows me also knows that for the past four years I do attend the lobby day that is arranged by Equality Maryland, and the local politicos do know about me from that. Could I do more? Of course, but I don't feel that standing at the National Mall is the way to do it.
In the meantime, I hope I can be proven wrong about the number of people taking action, but we'll see. I would hope that people would take the time to write to their Congress and their state politicians to let them know about getting equal rights. It is still my theory that the more states that allow full and equal rights for GLBT people, the more pressure it puts on the Federal Government to drop policies like the Defense of Marriage Act and Don't Ask Don't Tell. This would especially be true if Maryland would become more about equality as well, since lots of feds do live in Maryland...