Those leeches (note correct spelling) bid for the concession rights to operate the FBO, and landing fee income is considered in their bid and are an important source of revenue for the business. They are allowed by law to collect it. It's also common for FBOs to be required to pay part of the fee to the airport owner.
While taxpayers that have nothing to do with GA pay the airport grants and local government taxes (thereby partially financing your flying), you as a pilot are a direct user of the resources.
It's comical you splutter about "taxpayer funded resources" that directly benefit you, but you're too cheap to pay a small additional fee to support your activities.