People tend not to attribute random spam filter breakdowns to the humans moderating content, other than when a specific person suffers over it and takes especial umbrage. It’s more likely that people who visit the story will now have a slightly worse opinion of OP, which sucks because OP is using a poor method to make a good report of a meaningful problem that needed solving. Methods matter! This meeting should have been an email.
Are you asking them to be specific about what they dislike or something?
I feel like the answer to "What practices?" is obvious: "The reason the submissions were being killed is that the GitHub account's address had been banned on HN due to previously being submitted by spam bots."
I was wondering what “moderation practices” related to this story they thought warranted people having a worse opinion of HN moderation? It's unlikely they were referring to automated spam filters.