Your analogy is silly. Going to the moon didn't break any laws (well, except maybe the laws of gravity at the time, LOL... ahem), and was done to better humanity through learning, which is why it was widely approved and celebrated. Clearly Blizzard did not approve nor celebrate the use of creating infinite herbs, whether for amusement or money, and in fact said not to do such things in the ToS people agreed to beforehand. Also, I highly doubt anyone learned anything from it besides "my friend/the forum post that told me about this was right!"... well, that, and that Blizzard really will ban you if you're bad.
Saying you were curious is not ever a valid excuse to break a law. Every crime in the world would be excusable if that were the case. "I was just curious if I really could get home with a blood alcohol level of .3, I didn't think those people would still be awake and on the road with me at that hour!"
Curiosity is natural and innocent - knowingly breaking a rule purely for fun or personal gain is not innocent in the slightest. If you know you're forbidden to do something, but do it anyway, it's intentional, and it's not curiosity anymore - it's mischief. Wondering what a view looks like from the top of a building under construction is curiosity. Pushing past the signs saying 'Do Not Enter' and crawling through a hole in the fence so you can climb it is mischief, no matter what you don't disturb and how pretty the view is.
I can't tell you that thirty thousand people did this all for profit, but I can definitely tell you that not one of them who didn't report it actually thought they were doing something allowable. They may have thought that Blizzard would turn a blind eye or not notice, but I guarantee none of them thought that a method to create infinite herbs was legitimate or okay. That people like the OP only did it to test it, but not profit from it, shows that they knew it was morally wrong to use it, or else they would've gone to town with it. They knowingly dangled their toes over the yellow line hoping they were safe as long as they didn't put an entire foot over it, but this time they happened to be punished for it.
And no, just because you think it's good clean fun doesn't mean it's harmless. You're essentially slapping Blizzard or any lawmaker in the face by thinking you're above the law because you can do things that you personally don't think effect anyone else, which just opens the door to doing more things that you think are in good fun, until stuff hits the fan. If you're going to do something irresponsibly, you know by its very nature that there are multiple outcomes, but still have to take responsibility for all of them. Just because no one knows doesn't mean a minor can legally get drunk in their own home and that they're guilt-free the one time the police or an ambulance is called. Poking the items in the 'do not touch' display case is all well and good until you break something. Even something simple that doesn't seem to have any unfavorable results can still go horribly wrong - being able to walk through walls to explore in WoW is all well and good, until you have to explain to the GM how your character is completely stuck, naked and upside-down on the spectral sandbox tiger on GM Island. Finding a way to transmog Thunderfury won't hurt anyone (and would be awesome!), until the one day you forget to take it off in town or an LFG and it spreads like wildfire. It's only a matter of time, and for these people, this was that time.
Besides, Warcraft already has a red button in Ulduar that says you should not push it, exhaust your curiosity on that if you must.