I have not read this entire thread and maybe someone has mentioned this, but this year UF ended up playing two D1 FCS teams because Idaho dropped down from D1 FBS to D1 FCS between the time UF scheduled the game and when it was played. That is excusable in my view.
Other than that though, I agree that UF should not be playing D1 FCS school as a rule. The only reason to play D1 FCS schools is to save money on the fee and maybe it is true those schools to not demand as big a pay day as D1 FBS non-power 5 schools. Of course if all D1 FBS non power 5 schools are no longer willing to play a game without a return game, then that would be an addition reason to schedule more or maybe even all D1 FCS schools.