I hate to say I think you're cheap, but ... I think you're cheap.
Is it the fact that you'd simply not pay for it? Because bringing in a fee brings in a choice, you either pay for the goods or don't get the goods. In the GP32 scene the market is not big enough, but multiply the scene by 1,000 or so and would all these free emulators be around? Probably not. Open source-ish hackers would move on to a smaller platform, most programmers would ask for a bit of money to compensate the work they do. Some emulators are commercial with no free alternatives, because the work involved is monumental, and nobody is willing to do it for free. Rlyeh and others ask for donations all the time, and somehow if they work and expect donations, it's alright, but if someone specifically asks for donations before parting with their work, it's wrong. Oh no, they shouldn't be allowed rights over their own software!
As don said, a bunch of chips interfacing is usually not 'owned' by a company. That's why many consoles have bios that are copyrighted or somesuch so that you need the original one to own them. I would have thought, on a moral level, that as long as an emulator contains no roms or bios images, that it really contains nothing to worry a company about, since it is the user, not the emulator author, that is breaking the law.
We pay for a product and a service. People who do the work to replicate this hardware as software spend labour time, and are reimbursed with money. It doesn't matter what that work is; it's work. Now, people sometimes grab Mozilla and OpenOffice, rebrand it and charge for it. They've done very little work for what they charge, but it's legal. Unfortunately selling emulators may or may not be legal, but usually the authors do a lot more work than they charge for. You can either put your money into the unscrupulous bastards that con others, or into the honest developers for making your portable system a little more enjoyable.