I can't legally pirate Windows just because the source code was run through a compiler. Even though the compiler itself adds no additional creativity, the underlying source code is still a creative work[0], so pirating the binaries still infringes a copyright. Just one that's in a slightly different place than what we're normally used to thinking about.
Just to drive the point home, there's a few other situations in which copyright "flows through" to things not subject to copyright. Back in the days of copyright formalities, if you published before properly registering something, your work would be born into the public domain. And this occasionally happened to serial media - e.g. someone might just forget to register the third season of a TV show. In that particular case[1], seasons one and two are still copyrighted, and because season three is a derivative work of the prior season, nobody but the original owner can actually make any use of season three. The only practical difference is that the company that owns that TV show lost one year of copyright ownership over the third season.
[0] By definitions of law. I honestly think most software shouldn't have been made copyrightable, but once Congress said "software is copyrightable" that put that question to bed.
[1] I don't remember the name of the TV show or the court case, but this IS a thing that happened and this theory IS court tested.