There is no limit or fine line as to whom you can or cannot criticize. It is a behavior that some possess and often exhibit based on personality regardless of the situation. I believe most (Boosters, Coaches, etc) have the maturity to understand that, and are not impacted by meaningless dribble from those who feel they know all and are readily willing to share in whatever opportunity presents itself. It's the current and future student athletes that I worry about.
I have reached out to moderators in the past encouraging them to monitor and address negativity on this site to no avail. It has become increasing difficult to find useful information and share support for the Red and the Blue on this site. Maybe a new site will emerge that will have better administration and meet the needs of true pony fans.