How is this fair ???

I am a stay at home mum, through choice so I can be there for my children, but it also means I don't have quite the same income as before which is fine my childrens happiness is more important but I was out the other day with the children and my eldest saw a sign advertising free sports activities ie basketball, football volleyball etc and free swimming and ice skating entry amongst other things. We decided to go in to ask for more information and the woman replied sorry your children are of a normal weight and so do not qualify!!! Apparently this is for the parents who do not bother, not including people with genuine medical weight problems in my rant, and let children eat all the cr** they want and are now overweight and obese who get these freebies but never mind us decent parents who take care and pride in our childrens health. Can someone explain the fairness in this, does this not just make some people wonder why they bother???