Well, this race was "effectively over" on March 4, though it would have been a good deal more awkward for Hillary to drop out after two big wins than for Tsongas to drop out after his losses. Plus, Clinton has won a lot more states than Tsongas. Of course, the analogy isn't perfect, I think both in this example and the RFK example, Clinton was going for pedagogy rather than precision, and there will be a cost to that when speaking to the highly informed political class, but there is a benefit in relate-ability when speaking to more low-information voters.
Well, obviously, but that doesn't make her analogy any less intellectually dishonest. Stupid catering to "low-information" voters, whether it be George W. Bush asserting that Saddam Hussein has ties to Al Qaeda or whether it be Barack Obama using idiotic catchphrases to mask substance or whether it be Hillary Clinton giving asinine justifications for her continued presence in the Democratic Race exemplifies one of the largest flaws of the American political system. One of the [many] reasons why I'm having some difficulties taking this race very seriously.