But why? I will think this through in writing, because I think better in writing.
I'm not talking about ordering one's employees to "Vote for X", which would go from "creepy" to "is that even legal?" (Although really, how is your boss going to know who you voted for? Still.) This is CEOs sharing their political opinions with their employees , and is the sort of thing I would have no objections to in a context other than "CEO directly to employee". People, even CEOs, have the right to express their opinions on politics. I would have no qualms about a CEO writing a blog post or a newspaper op-ed about who he thought should be elected. But sending it as an email to his employees? Ewww. Creepy.
It's an unfortunate truth that politics affects business in many ways; I expect that the CEOs who tell their employees that Obama's re-election would "threaten your job" genuinely believe it. They think that Obama's policies will have a negative impact on their business which will cause them to lay off employees. It's not meant as a personal threat -- "vote for Romney or I'll fire you" -- but gosh, kinda sounds like one, doesn't it? Especially when it's part of a direct message to you. That's a big part of what makes it so creepy. It bugs me that the Huffington Post wrote the article and headline as if CEOs were making personal threats to their employees, but frankly, it's not hard to make that leap.
It also feels terribly unprofessional. This is not a business communication. The business climate in America maintains the polite fiction that business and politics are separate and that a person's political decisions do not affect their job. This is patently false on a macro scale -- of course the government we elect affects the businesses we work at -- but it more-or-less works on a micro scale. My ability to create reports or balance accounts is not impacted by who's president, or by the way I vote. I can understand business communications opposing or favoring specific laws targeted at their industry -- "this is how this proposed legislation on bankruptcy will affect our bank" --but talking about Democrats or Republicans in general is too far removed from any business purpose to be professional.
And if there's one thing a CEO ought to be, it's professional. Sheesh.