Earlier quoted context omitted.
At the very minimum it should be taxed the same as dividends. Essentially tax buybacks are a tax loophole for giving money back to the shareholder.
Another word for "a tax loophole" is "the tax law". The fact that ham fisted bureaucrats and legislators create unintended consequences with every "incentive" they put in the code makes it no less binding.
If you think those consequences are unintended, then I have a bridge to sell you.