However, if I encounter users that I think are muting people out of spite or too liberally. I will likely unfollow that person because I know they're shutting out potential ideas etc.

"Think" is the key word here, we have no public record of who someone mutes. The only way this can possibly get back to you is posts like this.

If this site gets larger, then there will be a flood of "I was muted by X" posts. It will be impossible to keep track of them all and deal with them all at an individual basis. In fact, malicious users could fight back. I could right now claim that YetAnotherAccount muted me in a new post. You would have no way of knowing if I was telling the truth, and if YetAnotherAccount joined the conversation and said "nuh-uh", then it's a he said she said situation.

Every single post in a larger scale version of this site would be impossible to verify, and the mute feature would just become a rampant abuse not just from a direct feature standpoint, but from an argumentative standpoint. It would turn the users against each other, make the site an arguing site, and mass bot sign ups just to make false accusations would drown out the real accusations.