Nah, they're all just butthurt men who think that "only THEY can draw half naked アニメ characters of the opposite gender!" In all honesty, those people are complete and utter idiots who need to learn something called ~Equality~
But yeah, that's basically it. によって fanservice, they think that this 表示する is a girl's equivalent to their "Women Stripping" アニメ and they aren't happy about it.
Seems like this アニメ is centered to girl fans. I think it depends on where あなた will focus on. If あなた want to focus on the muscles, then go on. Nobody forces あなた not to. In their case, that's what they had their heads on!
Although I also think that the funny scenes (Haru getting all worked up on choosing his swimwear and Rei with his "beauty-fetish" are the funniest!) and the ハート, 心 pounding tournament is worth watching, since personally, I really like sports-themed animes that can make me feel excited, ever since Prince of Tennis, to Eyeshield 21, to Giant Killing, to Kuroko no Basket, and so on. The theme is also about team competitions and friendship.
It's not all ファン service. (Tho, yeah, but not totally.) It's not ecchi または hentai または anything like that. No groping または molesting is involved. Just pure men with half-naked bodies trying their best for their swim team.