I don’t see how Rav Chaim’s psak shtims with the ads for Stop the Talking in Shul. In those ads, it says Rabbi Eytan Feiner (of the White Shul) ask Rav Chaim how much his shul should spend on security, to which he replied that if they stopped talking in shul, they wouldn’t have to spend anything.
Yaakov Doe, your niece in Texas told me that lots of congregants there carry weapons. And it’s common for people in some shuls in Israel to carry.