X comrade is not being nice. Y comrade must write more gently. Z comrade is too harsh when speaking with others. Especially when speaking to non-Marxists.
What these folks seem to miss, is one of the many many lessons of dialectics. Sometimes you should couch your Marxism in gentleness, sometimes you should couch it in fighting terms. The more mature you know your audience to be, the less gentle and more fight-y you should be. The best tactic is always the most successful and principled one. The important thing is, people should dispense less advice and instead show-by-doing. Just jump in the fray, make the argument you wish had been made, prove your point. There's too many backseat drivers. "if you only said it this other way it would've been a hit..." Prove it! Gentleness, politeness and so on has its place. But then, shunning manners is a very western attitude, and thus we westerns are pulled in the opposite direction. Contradiction!
'Just jump in the fray, make the argument you wish had been made, prove your point.' Don't overthink this part. Jump in, try it one way. And if it doesn't work, try the other.
Practice will show what works.