And yet, having to wear spurs has not stopped them from competing, nor does it seem that judges have penalized them enough for their poor riding to force them to improve.
I’m in favor of spurs being optional. In an ideal world, they require a more educated leg to use, but that has stopped no one in the history of ever from using them. One could also argue that not having spurs could demonstrate a rider has an even more educated seat and refined aids! (Again, ideally, though perhaps not realistically when it comes to looking at competitors)
But at least in the context of modern dressage competition, the tests are about the education/training of the horse, not the rider. Unless that changes anytime soon, I’m in the camp of “allow for less” because requiring more equipment won’t stop anyone who has a capable horse but less than capable skills from competing and (mis)using said equipment. FWIW, I feel similarly about double bridles.