Many mobile emulator Devs are like that unfortunately, no desire to improve things for the emulation community, AetherSX2’s dev was like that as well, though he went a step further and sold to a Chinese dev team who put ads and malware in it.
There is no valid excuse for locking down an Emulator, it’s either to hide the fact that they used SDK material or because they want to sell it later, either as a product to you or sell it to another Dev team (can’t easily do that with open source as it’ll be forked and the buying dev will be labelled shady or bad by the community). Saying “to prevent plagarism” is a Bullshit excuse because as well, Android did and still does have a thriving open source community, they don’t do it to prevent plagarism, they do it for money or to hide their own plagiarism (SDK or copying GPL code).