If by gay you mean happy, maybe it's because they just got their nails done.
Crocodiles are like most crawling reptiles in that their legs are attached so they stick out to the side, rather than down like a dog or horse. Their legs just barely lift them off the ground, and don't have much flexibility. So they walk in a twisting, side to side motion. A person who walked this way would seem peculiar. But a croc is 100% serious. By the way, this walking motion is very useful on muddy surfaces like river banks, and underwater where crocodiles spend much of their time. (And if you ask a croc, he might think you walk funny, too.)