You’re getting downvoted but you’re correct. I worked in the pharmacy industry during and before COVID. Ivermectin, as a pill and cream, were being used for a variety of things, human and animal; it wasn’t the most common medication by any means but we always had it in stock and filled it regularly, until the COVIDiots (patients and doctors!) decided it was somehow the cure and started flooding us with prescriptions for the stuff and we had to stop filling them.

All this to say, unless Rogan has parasites (not ruling it out), no reason to be taking dewormer, horse or otherwise.