But it is a government intervention. No banks were willing to give them that loan. Government gave them money when nobody else wanted.

The loan was subsidized; commercial entities wouldn't give such a loan, hence even when repaid was a cost to the public. The idea, of course, is that this cost is paying by public good, but Tesla mis-stated the truth, and didn't grant back the public good it was supposed to.

Tesla got preferential treatment from a government entity and benefitted from public funds.

Also the government subsided them by effectively paying a portion of every Tesla sale price for a long while.