There are things that can't be written down without hidden (or obvious) judgement. This is one of those.
For example: "I don't want to judge, but I bought a gallon of milk three days ago and didn't get to use a drop of it." My concern isn't that you feel bad about drinking the milk or to paint you as a milk thief to others, my concern is that I bought milk and I didn't get to drink it. I'm being forced to offer a judgement in order to talk about my own experience.
What you do is that you just don't say it... that's what you do if you're actually concerned about painting someone in a bad light / don't know if the fact applies at all.
The idea of “pretending” here is interesting, I find the whole “ I don't want to judge him” to be its own form of dishonesty….