If the charters didn't have night flights, the aircraft would lose around a third of possible flying time (and incur the horrendous charges the airports impose for parking) - loss of that sort of revenue would send the price of packages/flights through the roof. Margins are way too tight to accomodate that sort of loss without affecting prices.
Individual arrangements with foreign hotels will affect check-out times (that is the hotel's right to ensure they can get rooms cleaned between clients dependant on local labour). If you are lucky, with an early morning return, you may get to keep your room til perhaps 4pm (or "purchase" a day room if available) - I would agree that 10am seems a bit premature, but it is not unique
salutory lesson 1/ choose whether or not you want to take the - cheaper- night flight option and accept the inconvenience 2/ - ASK the question when you book - what time is check-out of the room??
Boy is it easier to be wise with hindsight
We loathe night flights to the extent that we will travel 150 plus miles to an airport which has a better time schedule rather than accept the night flight from our regional airport (which would mean hanging around aimlessly with the kids in resort waiting to fly home) sometimes however a night flight can mean a days annual leave saved, less petrol/parking costs, less ££££ (we paid £83pp daytime supplement on one occasion which was horrendous - but at least had the option to make a choice)
This applies to every charterer - watch the flight schedules! the BY's, TCX, FCA, MON's all work flat out, rarely do any of them have more than an hour to an hour and a half on the ground at any time day or night.
Check out ceefax (pages 440 onwards) for your local airport an hour-ish before your departure time to spot where your aircraft is probably coming in from. (Keeps my 11 year old occupied working backwards on any one particular aircraft to work out where he THINKS it has been all day!)
They are on the ground just long enough to unload, reload, recater, clean. Flight times depend on what flights the aircraft has already operated that day (plus to some degree the slot/parking stand availability ). It is NOT a sadistic plot to delay a departure to 00.30 just to deprive you of a room for the night - the situation would be the same if you left at 23.00 or 03.00 from the UK.
Easy to be wise after the event isn't it (do I sound as if I'm lecturing - sorry!!)