>>126860861Because Aquaman is a founding member of the JLA. Every member fills a niche within the group, Aquaman is quite simply the water guy. Which many don't see how important that role is since most of us humans don't put attention to the oceans because we have "tamed" it with technology. Which isn't true, even today with the most advance ships, we truly are at the mercy of the waves. You don't know how hapless and vulnerable one's feels until you're in the middle of the ocean. There is a reason why ancient humans have always shown chaos as sea monsters, it is a domain we humans are alien too.
The oceans and the marine creatures living in it have a big impact on our environment. Rising water levels and warmer currents year around are creating more storms, not to mention more animals like sharks to venture closer to where humans like to swim. Our misunderstanding of the ocean is why shark populations are low and they're what keeps balance in the ecosystem, which means food will be harder to get from the ocean. Which only adds to the overfishing we humans are already doing. No food will lead to people fighting to resources be it crime or wars.
The ocean and other waterways are important to trade which means opportunities for crime. Batman doesn't patrol past Gotham, so who stops the tankers smuggling drugs and weapons from even getting to Gotham? Aquaman. Who is there to stop Lovecraftian horrors from ever reaching our shores? That's right Aquaman. Who's going to keep Atlantean and human relations good so they won't invade or destroy us with epic floods? Aquaman.
Aquaman is not a joke character, he is the ultimate symbol living harmoniously with the Earth and the reason many people think he is a joke speaks more about us not understanding the ocean.