Maybe at your mountain thats true, but at most places i go everyone knows what they are doing.
I do understand what you are saying though, more stupid snowboarders in the park than stupid skiiers, and here is my logic. Snowboarders feel and obligation to go through the park, it has been part of the sport since its inception and continues to be the driving force behind snowboardings progression. While there are racing leagues for boarders, racers make up an infintesimaly small proportion of the snowboarding population and consequently the snowboard community at large doesnt feel it doesnt have the same number of subcategorical outlits that skiing does.
So ya there may be a couple "weekend warrior" snowboarders who think they can ride the park, thats probably true. Most of the time they are there because they think owning a snowboard imediatly makes you hardcore, and justifies getting 'extreem'.
In the same breath its not fair to label all snowboarders as 'stupid' snowboarders. While we skiiers always claim that we go bigger and better, the simple truth is that a majority of our style, ALL of our terrain parks, and loads of our tricks came straight out of snowboarding inovation. Even the idea of shaped skis, which has revolutionised the sport for park rats and racers alike, came DIRECTLY from snowboarding.
In summary its aight to rip on local 'Joe Douch' who does some stupid shit like putting picnic tables in the landings (why would they do that by the way?), but remember every time you carve a sweet line, hit a jump and do a 'Cork 5', or slide a rail, remember that you're standing on a platform that snowboarding built.