This one comes from one of my favorite cynical jerk types, from way back when. He was a free thinker who loudly and vociferously advocated free thinking in others. He publicly attacked institutions which at the time were against such, and he wasn’t careful about who he offended in doing so. I won’t link his stuff since it is very well known:
“Every man is guilty of all the good he did not do.” – Voltaire.
Short, sweet, and pretty preachy, but it makes a good point. The quote is for this event: