Tudor,
To answer your questions:
I knew having children would not be easy but decided to perpetuate the human race. Having read your post, it is reassuring to note you decided not to.
My children travelled on company supplied full fare tickets with a baggage allowance. So junior was subsidising your drinks, newspapers, food, carry-on, obesity etc.....
I would respectfully suggest that unloading half a dozen buggies would not materially delay delivery of your (admittedly precious) luggage.
The airside bus is not complementary - it is included in the ticket price. If, as you say, buggies are not allowed on buses at Gatwick by the bus drivers this gives an interesting perspective on who runs the airport.
As explained above, there is no reason why buggies have to be carried up rickety airbridge stairs - there is a full specification stair case right next to them.
I would suggest that a child in a buggy on a bus is less likely to injure someone than a hot shot executive swinging his 25 kg carry on and duty frees.
I like to live in a society where a little care and consideration is shown for ones fellow man, and am prepared to accept the overall cost to society of doing so. One day, you will be old, tired or ill and may appreciate these little courtesies. Until then, please wait patiently for your luggage!