Various commentators in the past have suggested that without airport subsidies, Ryanair would not make a profit.
Ryanair take people to where they wish to got to at an affordable price. Making money from the aerodrome is the responsibility of the airfield operator. It is that simple. Some can do well with FR, some couldn't negotiate their way out of a paper bag, those, not doing so well.
It's business, and it meets local government(!)