Name aside, what's the difference?
Copyright Infringement: You work on your super secret business project and someone gets into your house copies all your work on his external harddrive, and then release the product as his own, you still have your product, so you can publish your version and compete with the Copyright Infringer with better support, more functions available in the product... You most likely do not get all the money you could when you would be only person in the world with the right to copy your work, but you still can make nice living out of your work and continue to make your product better and better, despite the leak...
Stealing: You work on your super secret business project and someone gets into your house and steals your PC, all your backups, including the backup in the cloud, and then release the product as his own, you are ****ed right in the ass, because you lost everything all your code, all your notes you had and possibly go bankrupt...
Hopefuly you now understand the difference between Stealing and Copyright Infringement...