Going out in large numbers hurts the process, it doesn't help it. People think everything is like civil rights or something, and you just do things in large crowds and people listen. In a case like this, a lot of people are afraid that legalizing pot would lead to a bunch of young people becoming potheads. So you hold a meeting where people can see thousands of young pot heads on the news? That only makes things worse and has people saying "I told you so." I guess that strategy makes sense to a pothead. O.o
If you wanted to actually make a point, all people who supported legalized pot would hold gatherings and do everything but smoke pot. To show that they are A) not addicted, and B) normal people who refuse to be defined by a drug. Or just do the whole smoking in large crowds thing and increase stereotypes, I'm sure that will change minds.
Thankfully the potheads are dumb enough to slow down their own silly cause. =D