Sorry you feel that it is not tznius to stand up for what you believe in. Sometimes one needs to speak nicely, and other times one needs to be forceful (have yet to hear a valid argument that we are not being nice enough to Hamas). Speaking harshly or forcefully in not necessarily counter-tznius whilst speaking nicely is not necessarily automatically tzanuah.
Additionally, one often bring these things onto themself the way they choose to behave and initiate. He was not apologetic, and he himself acted with a sense of entitlement no wonder people were not nice to him. We see that Yaakov avinu blessed his sons that THEY be balei rachamim when they go down mitzrayim to negotiate the release of their brother. Why did Yaakov give this blessing? Because the only way the Egyptian viceroy would have mercy is if they themselves showed mercy. NEVERTHELESS, LOOK AT HOW FORCEFUL YEHUDA WAS WITH HIS WORDS!! WAS HE NOT TZNIUS?