Haters gon' hate.
You can't really stop it unless you start warning for them being immature about it. Which I really feel as if some people will find this unjust for you not letting them hold their own opinion, then you got people complaining about everything.
But I have to agree 10 times over, you have to have respect for the people higher above you, even if you have issues with them or how they do what they do. So if you need to complain, do it in a way not as harsh, maybe point out the staff members flaws to help them improve? Just not in a completely disrespectful way.