Re: is he still a US citizen ?
Yes, it's rather droll that USians have to pay income tax on earnings abroad that presumably never touch US soil, but apply that thought to US companies (e.g. Apple with ~$200Bn abroad)? Never, perish the thought.
Surely with McAfee's wealth he could make a new McAfee Inc to hold all his cash abroad and be immune to this, employing Trumps accountants to certify that haircuts and other living expenses are actually tax deductable, so that they can't come after him that way? It costs <£100 to register in the UK, and I'm guessing similar order of magnitude elsewhere, so it probably makes financial (if not ethical) sense...