As much as you would like it to be, copyright is the status quo not per see the ethical choice. It's also not the only way to remunerate creation.

I don't personally care about copyright. I don't pirate video games because they are generally artistically as interesting as blockbuster movies which is to say not at all but I don't really have an issue with people denying profits to the entertainment industry.

Writing emulators is fun in and of itself by the way. I don't think most of the developers use them to play.