What about Rebbetzin Jungreis?
I don’t claim that it is assur for a woman to speak in front of men. It is a sensitivity, and depending on the circumstances and the need, it can be appropriate.
Popa: Based on what the Kitzur says is the worst Avairah possible, Tznius is probably the most important thing in the torah (Simin 151, if you need to know)
Sorry, I am unconvinced. I think that is down-right crazy to say tznius is the most important thing in the torah.
(And I don’t think that citation proves anything. I can find you somewhere where it says any aveira is the worst one.)