It is indeed for lessons - young people start to come in around 8. I swear there used to be a 7 and an 8. Now it’s just 7, there’s no spreading out over the two hours.
Yes it's leisure financed by people's gym subscriptions and taxpayers. It's not magicked out of thin air. So it's important that the resource is allocated efficiently. . It's also not leisure for the people working there for whom it's presumably a pain to deal with an overcrowded pool.