> A sentence must have a subject and a predicate, and a verb in the inf[in]itive form can't be a predicate
In the well-formed sentence
For cyanide to kill you, you need to be exposed to a lethal dose all at once.
Furthermore, idiomatic commit messages are pretty clearly not sentences, so I don't see why you think sentence structure should determine what they contain. And even on your own analysis of how the messages are interpreted (which I agree with), those verbs are infinitive, just as "fix" is infinitive in this dialog:
Q: What is this patch supposed to do?
A: Fix issue #351916.