Okay ... just for giggles, let's forget about the mola mola cowboy and just go over your last sentence, but in another context. If someone verbally harrassed your wife or girlfriend, but didn't lay a finger on them, would that be OK with you? I mean, they didn't inflict any pain, so no harm done, right?
Sorry, but IMHO your argument is terribly flawed.
Well, it'd be annoying but last I checked I'm not allowed to shoot people for being verbally annoying absent a threat of death/SBI. So I'd be stuck with either ignoring them or calling the cops about "verbal harassment" -- whatever you think that is.
More importantly, conflating the right of humans to be free from harassment and the rights of critters to be free from harassment is a
terribly flawed argument. Your average sea creature, absent some kind of legal protection (and often not even then, see 'scientific' whaling by certain countries), has no rights to not be caught, killed, cooked (optional in some cultures), and/or eaten. What's looked down on is the deliberate and unnecessary infliction of pain and suffering on the animal...but given a lack of outrage over sport fishing, it's hard to see how a mola ride is beyond the pale.
I'm very much anti-animal abuse: however violent nature may be, it's generally not malicious (though we see apparent malice in some of the more evolved creatures such as octos, dolphins, orcas, chimps, sea lions, et al.) and I don't like seeing creatures made to suffer more than necessary or without good cause in the first place. But at the end of the day, we're just another animal on the globe, and as we see constantly, various animals interact with eachother all the time in unexpected ways. Heck, sometimes
they come play with
us: dolphins, seals, sea lions, and octos all come to mind. And critters are not all delicate reef corals.
If you'd like to argue that riding a mola is somehow more traumatic for the animal than catch and release sport fishing of it would be, I'm all ears. Otherwise, I'll chalk it up to amusing and not harmful interspecies interaction. If the human isn't trying to hurt it, isn't doing anything so stupid they're likely to hurt it, and it isn't protected, I say go play nice with the mola.