I am an ex physicist and how statistics are handled by people who do not have the right expertise is exhausting.

He (or she, I do not know) wanted to show you that numbers you base your conclusion on must be carefully vetted.

I was once a reviewer of a PhD thesis in biology. The statistics part was dreadful, from someone who was otherwise a very serious student. She just would not know how to properly handle her data. After a review of the methodology the conclusions were different.

So do not get upset, being challenged by someone knowledgeable is fantastic and does not happen often.

Good luck with your degree.