Only a small minority of HN users are in Silicon Valley, so your argument wouldn't apply here even if it were true.
When I see complaints like this I always look at the history. Usually the account in question has a pattern of posting flamebait and/or snark. In that case you needn't reach for political bias or 'wrongthink' to explain why the community downvotes such comments. They get downvoted simply because they break the site rules.