Here’s Fr Cusick explaining:
https://rorate-caeli.blogspot.com/2019/06/when-twitter-mob-came-after-me.html
Interesting. It appears that he made this decision of his own accord though. I would disagree with him that priests shouldn’t opine on women’s dress outside of mass.
It is interesting that this did take place at a Latin Mass, and it makes sense that the woman in question was fairly new to the manner of dress at a TLM versus the banal Novus Ordo service.