“Software, by default,” is created with all rights reserved for the author.
I understand where you’re trying to go with your argument but if the author doesn’t have a means of legal distribution then there’s no way to have a legal copy on your computer to modify and run.
—edit—
And a license doesn’t restrict the rights to software but grants exceptions to the default “all rights reserved” copyright grant.
What? Are you really suggesting that software can’t be legally distributed by its author? And that a license is required before I can make copies for my own use? This is completely incorrect. What about fair use?
You can’t possibly have a legal copy of the software without expressed permission of the author. They may not care who does what with it (IDK, implied permission?) but they could change their mind at any time and chose to enforce their copyright. Which also means first-sale doctrine doesn’t apply as there was no “first sale”.
I also “make copies for my own use” of TV shows, written things, &etc and don’t think anyone would claim that isn’t violating copyright law, especially the producers of said content. In fact, I know this to be true as they have sent me nastygrams via email before. Also, by your reasoning, any company, like a cloud service, could take any code they want as long as they weren’t committing acts of distribution and use it however they want. I think we all know this isn’t the way it works because the anti-cloud licenses which have become popular lately would mean absolutely nothing.
And fair use is not really applicable to the current discussion because statically linking a library without permission isn’t fair use.
First-sale doctrine?
Which, ironically, doesn’t apply in this case since the software wasn’t legally distributed.