Just gonna debunk all these points real quick for you guys.
1) The crab trap design of the Krusty Krab is just a clever little reference Stephen Hillenburg threw in as a nod to his previous career. Remember, he was a marine biologist by trade.
2) This clip is taken completely out of context. In the scene, a customer and her son are eating, and the son says his krabby patty tastes funny. The mom looks at the patty and says, “Well, no wonder. It’s all old and dried out. Like that man right there.” And she points to Mr. Krabs. After the pair ditch the stale patty, Mr. Krabs tries it, and says “Huh. So that’s what I taste like.” He’s not commenting on the actual ingredients of the krabby patty, he’s making a metaphorical comparison because HE feels old and dried out. He’s having an existential crisis regarding his age. The episode is even called “Mid-Life Crustacean”, for crying out loud.
3) All of the main characters of the show are members of races that have very little representation in Bikini Bottom and surrounding areas. It’s not fair to point out the lack of a crab population as evidence for this theory when Bikini Bottom also lacks a sizable population of sponges, starfish, octopuses, plankton, whales, squirrels, and lobsters. Unless you’re going to suggest that krabby patties are made of what basically amounts to sentient paella, citing Bikini Bottom’s demographic homogeneity as evidence isn’t gonna get you very far.
4) NOT every menu item contains the main ingredient in its name. What the heck is Golden Loaf supposed to be? And are you implying that a Sailor’s Surprise contains actual sailors? Not to mention fast food restaurants typically name their signature menu items after the restaurant itself, not the ingredients. Jack-in-the-Box has Jackburgers, Whataburger has Whataburgers, Lotaburger has Lotaburgers, and McDonalds puts “Mc” in a lot of their item names. It’s a signature dish, so it’s named after the restaurant.
Besides, the show has already said that the patties are made of sea beef with a smidge of chum mixed in. Chum is not usually made with crab meat, and there’s very little of it in the meat mix anyway.