Interesting thread. I feel bad for the OP, but this is one of those things that's probably going to be difficult to remedy this far removed from the incident.

If there were previous temperature spikes to around 30C where active pool heating was not needed, then a dip back to air temperatures of 25C, then yes it's possible they could have dialed back the heating. But, that being said, if the daytime air temperature and the pool temperature were both at 25C, then the pool was probably being heated, as the air and water temp would not otherwise equilibrate.

Personally, I fall into the camp of the Finn and the New Hampshire person who previously posted - my summers growing up were to Maine, Northern Michigan, etc. Lots of cold water. And even living in Florida, the best treat in the summer is the springs, where the water is always 72F. That being said temperatures around 75 can be tough for swimming - you feel cold both in the water and out of the water.

Unfortunately not sure how far OP is going to get with this one; just strikes me as too much a matter of taste. In my recollection I've had more unenjoyable experiences with hotel pools that are too hot to offer relief in the summer than ones that are too cold to swim in. Seems rather a Goldilocks problem to me...