Mostly it was the high rates- The rate payers believed that the Undeserving poor (those who they thoguht were jsut being lazy) were getting off too easy
obviously the problems of the overseer- also a rate payer, un elected, and fined if not doing his job properly- came into it as running a poor house is alot of responsibility.
Other reasons would be increasing poor rate- economic crisis (industrialisation leading to lack of jobs, more poor etc) meant rates were increasing and the poor were more obvious- less room in the poor houses so they were on the street, more people were migrating to cities as well- introduction of settlement laws etc
In the North of England it was considered disruptive to put people into poor houses because of the cyclical employment so outdoor relief (food money etc) was given which was horrifying for the rate payers (of course!)
RvD. T. Malthus didnt help- principal of population -saying that the old poor law was unproductive
plus not only were the rate payers paying the rates they were also paying taxes because of the French war ending -recovery, soldiers returning to no jobs etc
-hope thats some help anyway x