While I do believe that loli/shota art shouldn't be illegal, the arguements they are making are retarded.
There's evidence that well known loli artists have used real pedophilic content as reference, so it does harm people. Saying looking at porn isn't the same crime as pedophilia, while true, is highly reductive on the role that acting as a demand has on the output of the supply of the material. I.E. It actively encourages more pedophilic pornography to be produced. Comparing homosexuality (and even transexuality) to pedophilia is fucked up due to one of the participants of pedophilic acts being unable to consent due to being too young to fully understand the situation.