The practical reason for ignoring lights is that if you want a critical mass it has to stay together, otherwise it fragments and your start to lose the safety in numbers. If a light turns red halfway through the mass, with 100 people through and 100 people behind, the 100 people in front can't stop and wait for the 100 people behind, otherwise they'd have to sit there and block the road for people coming from the other direction. It's the lesser of two evils.
Critical Mass is a bit like Reclaim The Streets - it's partly trying to make the point that cycling infrastructure in cities is generally complete rubbish, and one of the few ways people actually feel safe when cycling is to take over the whole road. People driving cars have this luxury every single day, and if they can't take a small inconvenience like waiting for a mass to pass, which often just means something like missing one set of lights, then quite frankly I'm happy to piss a few people off in the name of making a point.
I know it alientates some drivers, but to be honest I very much doubt those people would be persuaded by any rational arguments anyway, and I do know that a decent number of people who watch the mass go past are inspired by it.
Critical Mass is a bit like Reclaim The Streets - it's partly trying to make the point that cycling infrastructure in cities is generally complete rubbish, and one of the few ways people actually feel safe when cycling is to take over the whole road. People driving cars have this luxury every single day, and if they can't take a small inconvenience like waiting for a mass to pass, which often just means something like missing one set of lights, then quite frankly I'm happy to piss a few people off in the name of making a point.
I know it alientates some drivers, but to be honest I very much doubt those people would be persuaded by any rational arguments anyway, and I do know that a decent number of people who watch the mass go past are inspired by it.