That's the idea anyway (https://en.wikipedia.org/wiki/Crab_mentality) but honestly I haven't observed nearly enough crabs in buckets to say with confidence that it's typical for the species. It's entirely possible that a few asshole crabs have given them all a bad reputation and that I'm just perpetuating an unfair stereotype.
If I get the chance to get to know more bucket crabs I'm perfectly willing to change my view of them if turns out that they're largely cooperative and helpful.