In many, if not most cases, there are freeware programs without spyware that are available that can be used instead of programs that are in league with advertisers and use trackers. So the "how they keep programs free" is a rationale used for the public, IMO. They want to make money and spyware is how they do it.
There's also a difference between adware and spyware. For example, the free version of Opera has ads. You can read their privacy statement. Ads are displayed but it isn't spyware. I used that for a bit to try it out and then paid to support the product. That's one thing. But spyware (which the user wasn't or isn't always informed about before it's loaded on his machine) is something else. There's some real sleazeware out there and if any of them have cleaned up their acts its due to pressure from the antispyware folks and the proliferation of proggies that can detect and remove spyware.
Also some spyware stuff can really screw up your system or at least the performance thereof, so it's not entirely benign. And some make it almost impossible to remove without damaging your system.
Have you checked out the sites for Adaware, Spybot Search & Destroy and their related forums for info and/or input? There are some others out there as well with lists of programs which contain spyware. Here's the spyware info site (which also has forums) if you're interested:
http://www.spywareinfo.com/
What really gets me is there are programs (like some commonly used games..the egame stuff?) which you BUY and the software contains spyware (timesink for example). I don't mind paying a few bucks for something I want to use, but no way am I going to pay and still have spyware on my machine. It's my machine and internet connection if they want to use it for tracking sites visited, ads, etc, then they should be paying ME for the use of my resources.
But really I don't want that stuff on there at all.
