Most of the people I actually know who act in a "meet director" capacity (which obviously is a limitied sample size) are in a salaried position and this is basically considered part of their job. I would expect their salary to provide adequate compensation reflecting this time commitment, but because of the nature of that situation I can't really speak to what would be adequate compensation. I would personally feel usual hourly wage x hours worked would be adequate as generally there is a hospitality room with food provided, etc.
Personally I think that the meet fee charged to all entrants to the competition should be used to defray the meet expenses, although a lot of gyms do have team fees at the beginning of the year that also go towards those things. There is nothing that says they can't slap you with another fee (like a lot of dance schools here do a "recital fee" on top of costumes and tuition), but it sounds like basically what they are doing is making a "pure profit" by assessing extra fees and using booster money for meet overheads, and then keeping all the fee money. On top of this, they're taking booster money to recoup lost profit for a meet that they most likely ARE making a profit on. Again, for some of this, there's nothing (except market forces) that really says they can't do it, but it's a good way to run a business into the ground, even if you get away with it for some time because of a lack of competition. There may not be other gyms around, but there are other activities and of course people aren't going to tolerate ever increasing fees.