Just need to check with you. Are you going there on weekends? If
yes, the kids are off from school during weekends that's why they
have classes during peak hours, same reason as u. Normally weekdays
there wont be much lessons going on.
If they were to set a time specially for classes..and when the
public come in for swim, will be furious to find out. and the
complains will probably be more.
I think you just have to be more tolerant towards this and share
the pool.. 
