I philosophically agree with you, but the reality on the ground on US trails is that many people (dog owners or not) do not observe rules or etiquette. Go on a hike near Seattle and you'll probably leave with a Drake song memorized from how many kids are blasting it on their Bluetooth speakers. The actual trail is sometimes indistinguishable from the switchback cuts people make. Even take some time looking at US centric comments on this site lately: even with respect to a global pandemic, people will vehemently put their own wants over the greater good of society or the environment. The only solution is heavy handed enforcement. It sucks but I don't see a better way.