The analogy is inapt. It's not illegal to fail at parallel parking. Even if it was, it's not the type of offense that would get you arrested. You say the standards are different, and they are, but then you conflate the two contexts by treating both consequences as punishments. Failing a test is not a punishment. Failing at parallel parking is not legally or morally blameworthy.
It’s not illegal to misattribute small portions of a sentence either. There is literally no law against it. We harshly dissuade it at the grade school, high school, and undergraduate levels (meaning, we will give you a bad grade) because we are trying to teach young students not to misuse even a fragment of text with extremely harsh punishments outside of the legal system. We don’t apply the same level of punishment in real life and certainly not through the legal system because it’s not that serious to borrow a few words in the acknowledgement of a thesis. It’s just embarrassing and bad, as long as the concepts are original.
ETA: I say this as someone who has had both scientific contributions and entire introductory sections copied verbatim into other paper. That’s plagiarism. A meaningless sentence copied from my work has as much relationship to serious plagiarism as a fart in a car has to a Sarin gas attack.
You're using a different definition of plagiarism than Harvard uses. I also think Harvard's definition is overly broad, but that's not the point. The point is that a student would be punished for engaging in the same conduct that's at issue here. The double standard is the problem. The president of Harvard has broken the same rules she has enforced against the University's students. For them, the consequences are serious.
