Seems to me you're handling it the best way possible - yes, re-using open source code without proper attribution is an unfortunate mistake, but you've also clearly explained the reasons it happened. I also understand why the original code author reacted very strongly; when code is stolen maliciously and with intent, it's a huge "fuck you" to the original authors, who have freely released their code on the basis that they receive attribution of their use.
Good to see you've subsequently made up, and the code can stay. Thanks for being transparent, @ernest!
Seems to me you're handling it the best way possible - yes, re-using open source code without proper attribution is an unfortunate mistake, but you've also clearly explained the reasons it happened. I also understand why the original code author reacted very strongly; when code is stolen maliciously and with intent, it's a huge "fuck you" to the original authors, who have freely released their code on the basis that they receive attribution of their use.
Good to see you've subsequently made up, and the code can stay. Thanks for being transparent, @ernest!