I could see this schism starting to happen and it's going to hurt the movement more than it's going to help. Ideally, it wouldn't be taxed because tax's are evil and government sucks, etc. etc. We don't stand a chance of getting it directly to be legalized and untaxed. If we stand any chance, it'll be through paying taxes and even then, it's doubtful.
Marijuana is safe for you but it's still a 'drug' and there are societal costs by people who abuse it. They do exist and kids need to be taught to be responsible. If we have to pay taxes to let more people benefit from cannabis, then tax away.
People should be able to grow untaxed if they'd like (like vegetables) and the taxes should not (and simply cannot, to be successful) be as high as black market marijuana currently costs.