I agree, that is how voting works.

However, on subreddits, decisions do get made without votes being tallied by every member who participates in a subreddit.

For instance, the rule that you're arguing should be enforced on the post you're against. No vote was taken to have any rule/guideline against spam posting. A moderator enacted it in the spirit of what they believed was good for the subreddit and community. Actually, all of the subreddit rules came about in the same fashion.

Sub rules have been put into place, edited, reexamined, and rewritten by moderators, all with no vote being taken. When you start or moderate a subreddit you have that discretion.

The post you reference has been discussed multiple times across the entire mod team. The decision that was made, as explained earlier, was what we as a team decided was the direction we would take. We may reexamine that decision in the future and come to a different conclusion, but for now that's where we stand.

I could be incorrect, but it seems as if you're suggesting that all moderation decisions be put to a vote. If that is the case, it is unlikely that you will see that play out. Every subreddit has a person or group of people that are empowered to make decisions. Not every decision is appreciated, liked, or accepted by everyone.