sechel, re all the people who wrote letters to the LR:
Go through seforim of all gedolei Yisroel and you will find letters with very respectful titles to all sorts of people, including those of whom the writer did not hold. If everyone wrote exactly what they believed, and kept nothing of what they really believed to themselves, there would not be even two Yidden who would talk to each other. It’s only on websites like this one that anonymous people can voice their true opinions without fear of starting a war.
As to your quote about Rav Shach: he was close to rav aharon kotler who was a known misnaged
That’s not true. He did not like Lubavich, and he was indeed a Litvak, but he was on very good terms with many other chassidic Rebbes, as can be seen from all the work he did in Agudah and Chinuch Atzmai. Just because someone thinks that the Litvishe derech is the best derech, it does not necessarily make him a misnaged, and more than the fact that your thinking Lubavich is the best derech does not mean that you hate other chassidim… at least I hope you don’t.