A lot of people are competing for limited funding, so of course they resent the big bucks going into the ISS (I call it the "Good Ship Moneysucker") at the expense of other programs. This is especially true when you factor in all of the budget overruns that have forced NASA to canabalize other projects to make up the shortfall.

There's another factor as well: NASA has a well-earned reputation for poor management of big projects. Virtually without exception, every big NASA project over the last 30 years has been well over budget, often very late, and very often delivering less than promised. That's one reason why Congress isn't too keen on increasing NASA's budget for other projects like a manned mission to Mars. It just doesn't look like it's going to happen. You see, there's a lot of people competing for limited funding, and they see NASA funding as money that could be better spend on their projects, like roads, pork, welfare, etc.