The Rosh Av Beis Din of The Eidah Hachareidis in Yerushalayim, Rav Moshe Shternbuch, was asked (2:436) about someone giving a speech in shul on the political situation in Israel. Our shuls today are built with the intention (tnai) to be used for eating and drinking and therefore those activities are permissible. Should the same apply to a lecture?
He answers with an unequivocal no. Since eating and drinking have a purpose in shul a tnai helps. For politics, no tnai in the world would help. Even if the shul was built with these kinds of lectures in mind this would not help. Politics are “divrei chol” and they have no connection to religion. People think that anything that has to do with Eretz Yisroel is automatically kodesh which is in fact a big delusion. It is also a chillul Hashem since even the goyim would not hold political discourses in their houses of worship. If the lecturer is a Michalel Shabbos the situation is even worse.