The fact that many mammals instinctively do such solicitations doesn't mean that when humans do similar solicitations that's instinctive. Notably, instinctive vocalizations are involuntary; there are many mating signals that the animal makes regardless of if they want to. Cats wailing is (at least sometimes, like female cats in estrus) an example of that. Whereas humans declaring horniness tends to be voluntary and more conscious, as opposed to some of the instinctive vocal responses many humans do still have, like laughing when tickled or crying out when in pain.
Hm? I'm taking this all way too literally? Oops.
Also, for whatever it's worth, my reading of the initial post was more 'Horniness led to making poor judgement calls about appropriateness of material due to horniness lowering inhibition around things' and so made a mess of regular posting activity, rather than specifically going on the website to hornypost in fit of horniness. This would also line up with having made that post in the first place due to the lowered inhibitions of being short on sleep. And, well, even if I'm wrong, I think it's fairly safe to say "I will post horny stuff on Sufficient Velocity dot com in hopes of attracting other horny people" wasn't really the secret motivation behind the past problematic posting, instinctively or otherwise.