No, I agree partial credit can be useful in many cases.

Here is why I think it is petty in this case:

• assume grading is a tool to communicate degree of mastery of some concepts that are tested
• assume it is better to test concepts frequently, provide feedback early, and move forward based on those results – then there shouldn’t be a scenario where there are TONS of concepts being tested (or at least not for a quiz)
• if there are only a few concepts being tested, then does 2% really indicate any meaningful distinction of knowledge attained? Or is it as good as 0%? (I suppose the latter)
• grading takes work. This teacher had to look hard to find something that they felt indicated a few points, but that effort has little benefit to the student – who would likely benefit more from some remediation efforts than the teacher going through a quiz with a fine tooth comb.
• the teacher using this quiz to form their next lesson understood the kid needed remediation well before finding +2% partial credit, the kid’s grade is effectively the same as 0% and has no return on the teachers time investment to find this +2%, the kids morale is effectively the same as 0%, except worse now because there is an ongoing joke among their peers about the quiz. So all of the time the teacher spent grading this quiz has resulted in a worse outcome than if they just said, “wow this is bad, 0%, let’s do tutoring” and moved on.