It's common, if not inevitable, for people who feel strongly about $topic to conclude that the system (or the community, or the mods, etc.) are biased against their side (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...). One is far more likely to notice whatever data points that one dislikes because they go against one's view and overweight those relative to others (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...). This is probably the single most reliable phenomenon on this site. Keep in mind that the people with the opposite view to yours are just as convinced that there's bias, but they're sure that it's against their side and in favor of yours.
I could never say there's no bias—unconscious bias is a thing, for example—but I can tell you that we work hard to be fair, have been doing that for years, and there hasn't been any change in our practices.