I’m on month 135 of “no stirrups november,” so I can’t really say that I’m against it. I think riding at least one horse a day without stirrups has been the best thing (long term) I’ve done for my riding, generally speaking.
With that being said, I agree that picking an arbitrary month (which I was always under the assumption related to watching medal finals which then created an inspiration amongst young riders to do a “get ready for next year” type thing - and then also alliteration) and trying to do it all at once is not really a great thing for the horses. I think you’re much more likely to create a sore-backed horse than pick up a massive muscle gain…especially if you’re not riding 6-7 days a week.
BUT, I do think that dropping your stirrups for a few minutes to start and upping it from there is a great thing to aim for.
So when I read a title like feeling “ANTI” no-stirrups november, I read it as being a touch defensive and a bit of a contrarian whether that’s the intent or not.
To Brown Derby’s point - there are much better ways to build strength and balance. When I really want to torture myself I stand straight up in the stirrups at the walk, trot, and canter. I dislike the argument that “you can build bad habits” (because that’s a true for every thing you do while you ride), but I don’t think no-stirrups is the end all be all of exercise…just one of the easiest to incorporate into a daily ride.