Setting aside that professional licensure requirements are anathema to the spirit of the hacker movement, they would likely have prevented the creation of a massive pool of technology companies, including Apple, Microsoft, and Facebook. Even that proposal would stifle innovation.
However, what's being suggested by the OP is not even a professional licensure system.
It's mob justice.
The difference is that professional licensure organizations follow fixed sets of rules, procedures, and principles. These rules are established, agreed upon, and promulgated in advance of enforcement. Most importantly, the procedures generally allow for the basics of due process.
Mob justice has no set of fixed procedure, and no assurance of due process. Its enforcement is governed by caprice, and subject to a set of arbitrary, inconsistent, and constantly shifting "rules."
The OP is proposing an arbitrarily enforced "refusal to hire" policy people from an ill-defined set of "undesirable" companies.
First, there are no rules for establishing which companies are undesirable.
What fields of technology exactly are undesirable? And exactly how closely did an engineer have to be involved with such technology?
Second, many companies develop "dual use" technology, which has both civilian and military uses. This includes manufacturers of everything from CPUs to jet engines. Is the designer of a gyroscope used on spacecraft and on missiles banished from our ranks?
Third, many of these companies are also huge conglomerates. GE makes jet engines, as well as washers and dryers.
Where do we draw the line?
Should a GE employee be blacklisted under this "system"? One from Intel? How about Facebook for taking money from the CIA? Google for Boston Dynamics?
Most importantly, who decides, and how?
If it's determined by whim and popularity, as proposed by the OP, then I want absolutely no part of it.