It's a swimming pool.
Not a 'sauntering pool'
Not a 'bimble up and down whilst you chat to your friend' pool.
Don't get me wrong. I'm not what you'd call a good swimmer. I'm not all that fast. I'm getting better than I was, but I fully accept that part of the reason I go swimming is because I'm _not_ in as good a shape as I'd like. So I can hardly complain about anyone else doing the same.
However there are few things more annoying than a couple of women (It's true, in the last two years of swimming 3-4 times per week, I've never seen men do this) swimming side by side up and down the pool whilst yakking. It's invariable 2 (or even 3) people moving at the same speed as the slowest. And slower still because they keep turning around to chunter at each other.
I don't have a problem with you talking to your friends at the swimming pool. I don't have a problem with you swimming slowly. However when you're effectively being a 'rolling roadblock' to EVERYONE ELSE then you're just being rude.
(Oh btw, I found a new icon. Innit great?)