First, let me say I don’t think anyone did anything wrong here. I don’t think the OP did anything wrong, but I also don’t understand with the people who are so quick to jump on this Rabbi as someone who probably compromises on basic halacha.
But with that out of the way, there’s something that puzzles me about this whole situation. The OP states that she was having a conversation with this Rabbi about building community with other frum people that live nearby. Was she in this conversation unwillingly? Was this conversation adversarial? I mean, let’s build community with other nearby frum people and I don’t eat in other people’s homes seem like two opposite thoughts. Eating together, sharing a meal together- its one of the basic building blocks of community. Offering someone something to eat- its basic manners. I’m not at all suggesting that anyone compromise their kashrus, but if you start from the premise that you don’t eat in other people’s homes, I mean, the rest of the conversation about building community has got to be pretty short, right?