I agree. I've never understood why people get so worked up about steroids in sports when technological change -- Big Bertha drivers in golf and so on -- are the same thing.
Then there's the obvious reason for them to exist: to make money. These things cost about $550 per unit (paid for by your tax dollars for prospective Olympians) and, according to the article we've linked to, last for four or five swims.
More posts on performance-enhancement: