You're trying to make everything a perfect analogy for politics. It just doesn't work that way. If it did, there would be courses people would have to take and degrees they would have to earn to become politicians, just like there are for meteorologists and endocrinologists. Plenty of people who aren't politicians or who aren't experts in a subject can intelligently debate the merits of a political policy. At the most basic level, all politicians do is form opinions based on information they are given or glean for themselves. There's nothing that makes a career politician any better at doing that than any other person, like a CEO or general, who makes his living making decisions.
Well... there are degrees that relate to politics... specifically political science, public policy and law degrees (each dealing with different parts of executive, legislative or judicial branches).
And just like many other careers (including my own... computer programming), experience matters too. I work with several people with degrees in odd things who are accomplished programmers due to starting at a basic level and working in the field. We have a guy with a wildlife-fisheries degree who started as a programmer and has advanced fairly far. We also have an industrial relations major working in networking.
I'm a superior programmer much more because I've been doing it for 15 years, improving my skills and understanding of software development techniques than because I have a IS degree.
I'm interested in policy... but I'm guessing that Jeb Bush or Hillary Clinton would be able to discuss plenty of policy issues I'd be clueless on... because it's what they've been doing forever. I might be able to hang with them on one or two, but possibly not.
I can make excellent decisions on software development strategies, database design, networking and other IT issues that have been my career so far.
I can make reasonable decisions on business issues, accounting, costing, finance, manufacturing, industrial engineering, payroll, contract law and other areas I've had to learn a good deal about in order to program solutions for.
Can I make great decisions about education policy, economic stimulus or trade deals... even with great advice from experts? Can I work with legislators who have diverse goals to reach a governing consensus?
I'm doubtful. I've seen non-IS guys make idiotic decisions about IS-issues even with people telling them the pertinent information. Could I pick up much of the political knowledge and skill working my way up through various levels of politics? Probably. But I'm not going to be very good at any of it to start with.
I do wonder if people who think they know about politics and talk about it with career politicians elicit the same response I get when people who think they know something about programming talk to me about programming. I nod and smile at them, but inside my head I'm screaming at how little they understand what they're talking about/asking for.