I don't think there's an opposition to it. People just don't want to shoot themselves in the foot by gambling on Modafinil having no long term effects.
There is definitely opposition. It's mostly on religious grounds, a la "My beliefs dictate that I should prevent you from 'playing god', because that privelege is reserved for my deit(y|ies).".
Don't forget alcohol! Watching people climb up on a pedestal and try and tell me that alcohol is somehow not a drug makes my blood boil every damn time I hear it. I think it's hard to correct these people's thinking because our society drills the very phrase "drugs AND alcohol" into children's brains from a very early age including in the DARE programs in our schools. Somehow everyone is okay with casual abuse of alcohol because they don't think of it as a drug. "What else can you take into your body that fucks you up like alcohol does, but is not a drug?" is the retort I've been using in recent years.
There is definitely opposition. It's mostly on religious grounds, a la "My beliefs dictate that I should prevent you from 'playing god', because that privelege is reserved for my deit(y|ies).".