Rant: a guy at my Tuesday game night said house rules ruin games, and I still think that's gatekeeping
He refused to play our copy of Pandemic because we let new players see their role cards before choosing, and he went off for ten minutes about how we're not playing it right. Funny thing is, our group has taught 9 people to play that way at the shop on Grand Ave and every single one came back the next week. Do you enforce the rulebook exactly with new folks, or do you bend a little to keep people at the table?
Consider what that hard rule guy is really saying. He is basically saying the win matters more than the people at the table. If nobody comes back next week, he has nobody to play with, so what did he really win? Our shop group does the same as yours and the new folks learn the real rules fast once they feel safe asking dumb questions. Being strict with a first timer usually just teaches them the game is not for them.