That's understandable and fine really. The difference is that as long as freetrack uses the naturalpoint API, there's not much ground to stand on in order to claim that NP is doing something wrong. Sure, most of us can make the IR LED clip and find a webcam lying around, but not all of us can code an API.
Personally, i have a TrackIR4 that i got almost a couple of years ago, but i don't think competition is a bad thing, to the contrary in fact. The reason i got it was precisely what you mention here. I was between a X52 Pro and TIR4 at that point, but i decided to get TIR4 because of the official support.
The distinction for me in the whole deal is that i wouldn't feel comfortable saying "i won't give you money because i can build it on my own" and then double-back and go "don't change your API that i don't fund in any capacity whatsoever, because my free stuff stops working with it". That's why freetrack NEEDS an API of its own, preferrably something open-source.
Then, if NP is making backroom deals with game developers to stop supporting the freetrack API, you don't only have enough to argue a case of unethical monopoly, you might even have enough to take them to court
Until there's an open-source API for user-made head trackers however, there's not much anyone can do about NP changing their software as often as they please.