Fair is relative.
I can assure it will never be equal (fair and equal is not the same thing). Someones schedule will not be able to be accomodated. You are OK with moving it to earlier in the day, as the OP has pointed out it is a hardship for others. But you don't like the actual days, so that makes it unfair. And I am not picking on you specifically because we all have days and times that dont work for us.
They do the best they can.
Our gym has kids in at least, 5 districts, in 2 counties, public, Catholic and military. Working parents, 2 parent households, single parent, etc...They do the best they can for the majority of the kids.
My daughter has been on the end of not being able to attend practice when most can. And there have been times she could and others can't.
The gym does the best they can and tries to allow for make ups.