T-shirts are a way to make a statement of what you believe in and express your freedom of speech. It let`s people know they are not alone in their thinking.
It creates a visible message to the population that it is OK to think this way thus getting rid of the feeling of isolation people feel when they see someone expressing it.
Most people don't think twice to the fact that they are sporting a corporate logo and promoting that. In our case we want to promote messages of substance.
Freedom, if you don't use it, you lose it.