GRMember

Bald Eagle you can extract your own ROMs to use with an emulator. It's legal to make a backup copy of software you own.

It's also legal to create an emulator. Yuzu was shut down for reasons other than the emulator itself, for example they were making a lot of money off it, and they showed screenshots of games that hadn't been officially launched yet (proving they had unauthorized copies of Nintendo games).

Joe They're not stealing the code. When code is released as open source, the license grants anyone the right to use the code.

Depending on the license of the code, the company that's using it may have to open-source their own version of it (like the GPL license), but a lot of licenses allow the code to be reused with basically no restrictions (like the MIT and BSD licenses)