Actually, it does. If you don't have an OSS license, it defaults to standard copyright, which means TaxCloud has even less legal right to copy the code.
Drew could have used a license that legally granted commercial use without attribution, and in that case he'd have a bigger problem.
The author (or his company) always has the copyrights (if it is not sold) and thus can license it any way(s) wanted, for example und open source licenses.
Authors in certain countries can also release their code into the public domain -- that would be the only situation where there is no copyright involved anymore.
Drew could have used a license that legally granted commercial use without attribution, and in that case he'd have a bigger problem.