Oomis is a cranky old biddy (I’m just following her directive to call her that: http://www.theyeshivaworld.com/coffeeroom/topic/earplugs?replies=63#post-70558).
She’s 100% correct, though, and if it were me, I’d find a new shul to daven in.
As far as the OP, the rabbi’s behavior is beyond me. What would he do if he were a surgeon, bring the baby to the OR? I don’t think a regular mispallel should bring his child to shul either, even it means davening b’yichidus. I’m talking about men, kol shekein women who don’t have a chiyuv to daven b’tzibbur anyhow.