On the simplest level: If taxes take a big hike, then people are likely to move or rent out their properties. New properties aren't developed and people are less likely to do renovations/additions. This will lead to a decrease in the town's assessment value - not what a town wants!
As someone who lives in a town with a lot of NRTP's, and who has closely (very closely!) watched the budget process for both the town and the schools, I can tell you that careful attention is paid to any increases. This year our elementary school brought in a level-funded budget and our town pretty much did, too. Our high school had a slight increase of 2%-3% and it took a lot (and i mean a LOT) of discussion to get the budget committee to buy-in (and not all members did!)
In short, when there's a tax increase it isn't just for the NRTP's - it's a hike across the board and effects the year-'round citizens, too. Trust me when I say that the locals are even less fond of the increases. For many of us, this is the only property (our home) that we own.
Some things in life are inevitable and taxes are one of them.
