I mean the idea of forcing an animals head into a fixed position is kinda fucked for any reason other than medical treatment

The horse can’t use his chest, rump and neck muscles to distribute the strain of the load and can’t breathe naturally. Some breeds have a naturally high head carriage, some don’t, but either way, it can cause muscle strain, pain and chronic breathing problems. There are a few disciplines (dressage, for example) in which head carriage is seen as important to movement, but the humans participating in them disagree vehemently about what that should look like and how to achieve a correct form. Some trainers and competitors may go to an extreme, for example, “rolkur” (sp? Not sure), which is a very high collection of the horse’s head and neck, sometimes using the bit’s leverage to shape the horse’s neck and head against the pressure.