I noticed this as well, you are already downvoted into gray
I think this is one of HNs biggest weaknesses. If you are a sufficiently large engineering organization with enough employees that pass the self-moderation karma thresholds, you can essentially strike down any significantly critical discussion.
I'm sure both reasons happen to some degree, just as a matter of how often is actual astroturfing vs "a small percentage of active people can't possibly just have different thoughts than me".