” I agree that in shul it’s the time to talk to Hashem, but is it my business what the fellow next to me does? It’s none of my business. I go to shul to daven, Shoin!”
Baloney. It 100% most definitely is your, and every other Jew’s, business what the next Yid is up to. You are responsible for him, areivim zeh lzeh, not even mentioning the obligation of tochacha, you’re certainly responsible to care for his and every Yid’s spiritual wellbeing (ruchniyos) at least as much as his gashmius since his ruchniyos is even more important than his gashmiyus.