The overheads are a lot higher for operating in an airport. The prices reflect that. I'm sure they also add a bit on top for good luck but that's supply and demand for you. Don't like it, don't pay it.
The pick up charges are the ones that really grind my gears, because there's nothing you can do to control the cost. At least with drop off you're in and out quickly. With pick up there are too many variables.
At Manchester I'll pay to be dropped off at the door, but on pick up I'll arrange to be picked up at Wythenshawe town centre and get the tram to meet my pick-up. Otherwise, if things like slow baggage handling or long passport queues happen, you can end up with a huge bill.
I still think some people make it far more difficult that it needs to be though.
Especially as more modern scanners have come in at many airports where people leave laptops/ liquids in their bags.
There's no consistency, though.
I fly a lot compared to most people, I do 20+ flights a year, and I have to think about it every time.
The IOM doesn't have the new scanners (and probably never will) so it's the old rules- 100ml, plastic bag, and everything out. The security staff there are also very particular about boots; they make me take off my trainer-style walking boots whereas every other airport simply doesn't care.
Manchester has the new scanners and has just brought in the new 2 litre liquids rules. London City has the new scanners but the old 100ml liquids rules, although you can leave them in your bag. Liverpool is the same- new scanner, old liquid rules- and they're also a bit more fussy about electronics.
And that difference is just between British airports.