In the spirit of steeltoes' suggestion:
I think this is an astute observation. At the end of the day, we're only human. Our Us vs Them mentality tends to blind us to mistakes on our side, and magnify those on the other. So, we end up doing the same things that we revile in others; we just can't see it.
It's difficult to see problems when you are on "the Inside". I realized this in my deconversion from Christianity. Many things that made sense as a Christian fell apart upon scrutiny from a further distance-- on the Outside.
I think the real problem is that people are confused about what the sides actually are.