I don't think dying the chicks is inhumane so long as it's done using non-toxic substances. However, I agree with what others have said in that many people who purchase these chicks are doing it for the wrong reasons. They think the color is cute, that it's quirky, that a bright pink or blue chick will make a great item for their kids' Easter baskets. Oftentimes, these chicks are seen as disposable fad items and living toys rather than as animals that will need to be taken care of for the rest of their lives.
Just as the deal with cute puppies, many people get them on impulse without putting any thought into the fact that they're buying something that will need to be fed, watered, and housed and may have the potential to live for quite a while; that the tiny baby will not stay tiny forever and will at some point grow into an adult animal; and that young children will generally lose interest in such chickens when the birds lose their bright colors and are no longer tiny and fuzzy. Sure, generally, it's easier to get rid of an unwanted chicken than an unwanted dog if you don't mind butchering your own chicken, but it saddens me that so many people get animals (any animals) without having any kind of plan for them, any idea at all how to care for them, and any sense or understanding of the commitment involved in owning said animals, and/or even any real desire to have a pet.