Many years ago, the legendary Mashgiach of Yeshivas Torah Va-daas [later of Torah Ohr in Yerushalayim], Rav Zeidel Epstein, gave a shmooze in Yeshiva about the "piece of Amalek" that we ALL have within us. It is a common theme in yeshivos and mussar sefarim. When we talk about having Amalek within us it doesn't mean that we should obliterate ourselves. It means that there is something impure and unholy that must be fixed. When the board heard about this talk, they called him in and censured him for his horrific, vituperative words. All of his explanations that he didn't meant to be taken literally fell on deaf ears. He was warned never to say such words again.
Recently a well known [now more well known..] rabbi compared a large group of Jews to Amalek. All over the world people went ballistic. HOW COULD HE SAY SUCH A THING. HORRIBLE! UNFORGIVABLE!!
I am not justifying his comments. Rav Shlomo Zalman Auerbach didn't express himself that way. Nor did Rav Moshe Feinstein. But I think that his words should be seen in their greater context. He didn't mean that we should kill those people. He has lived for decades in the Jewish Quarter of the Old City where there is a large population of people who identify with the group he associated with Amalek. He davens with them, he listens as the baal koreh from their group reads the Torah, and his chazan is also often someone associated with this group. He also treats them with respect. I have watched him for many years and never seen anything negative shown towards those people. He was merely expressing - in extreme language- the large ideological gap between what he perceives as truth and what the group that he condemned represents. I know of a well known rabbi [who is close to many of my readers] who is famous for making very extreme, shocking and insulting statements. Yet, people continue to love him. When challenged, they explain "You have to take what he says with a grain of salt."
This applies to other statement we hear and that shock us. They must be seen in their proper context. The Satmar Rebbe used very harsh language against the Zionists but on a personal level he was ready and willing to help them - even with large amounts of money [a person's inner heart is measured by his willingness to shell out money. People of means used to say to me - "Good luck in your Kollel". I would think "You could actually make it successful if you'd like...." They didn't:-)].
Again - I am not sure that in our generation rabbis should use such invective. But when they do, I have 2 rules: 1] If they are big talmidei chachomim they still deserve our respect. Even if they are wrong - people are human and allowed to err. All disagreement should be stated with respect. 2] Their words should be understood in their greater context and with an attempt to determine what the person really means.
There is a lot more to be said on the topic, but I will suffice with this for now.