Love going to the beach, but why?

I love going to seattle’s beaches, but why do people who know they aren’t supposed to bring their dogs on the beach doing so? Dogs have taken over so much in the past 5 years, why can’t we lay on the sand not worried about being slobbered, kids digging in the sand not worrying about reaching poop, they’re linked to algae blooms, like why can’t there just be some places for humans? I truly am curious when it says no dogs on beach, why can’t that rule be respected? If you person does it the 50 others that are near will want to as well, so just why?