Shabbat before Purim, we read Parashas Zachor, which describes how Amalek tried to destroy the Jewish people. We read this portion this week, because Haman was a descendant of Amalek, and so many years later he tried to succeed where his ancestors failed, and didn’t learn from their mistakes. This reading is in fact the most important reading of the Torah, it is a commandment from the Torah to read this paragraph. That is why there should be total silence in the Synagogue so that every syllable, every letter, and every word can be heard.
Therefore it is proper to avoid speaking during the reading.
