Well, I'm glad you think that actually holding the government of the U.S. to the concepts expressed at its founding is "sheer stupidity."
Regardless of what you think (and frankly, regardless of what has happened historically with any of the active parties going back to the Whigs and Democrats), it is not the business of the government to invest, or to make a profit based on any perceived return on investment. There are several reasons for that:
1: It ain't Congress' job. See the Constitution (but we've covered that).
2: Once the government (in whichever branch) starts doing things like this, it's going to, by definition, be picking winners and losers. Let's say Larry Ellison decided to start up a new electric car company. Do we give him money as well? If we do, how far down the chain do we go when Bill Gates and the ghost of Steve Jobs show up with their new companies as well? If not, then we've given one (or more, depending on how far down the chain we got) an unfair advantage over the have-nots at taxpayer expense. Given all the squawking about making sure government is "fair" these days, that seems a bit counterproductive.
3: As romanval said, "traditional investors stayed away from" Musk. Why? Because it was a very risky investment. Great. We got our money back (and some profit to boot). In theory (this was just the press release: Musk hasn't actually paid us back yet). It does not strike me that loaning money to an entity that traditional investors are avoiding is being a good steward of taxpayer dollars.
Frankly, this is like a mother frog-marching her son back into a store to return the candy he stole, and then try to say, "It's all okay now. You got it all back, and here's a dime for your trouble."