BUT when they're just baseless attacks that have no solution or are completely unfounded upon. Then that's just trolling.
For example (I'll use my type so no one will get torn lol)
Bad: All INFJ's when reaching a state of unhealthiness should go to a mental institution.
Why: Unhealthiness was not defined. Could be just a white lie to full out murder. We do not know. Too vague. Therefore a useless attack.
Good: INFJ's can be overconfident about their visions and intuitions. They should withhold judgments until they read and understand the situation fully from all sides.
Why: A suggestion was made. Nothing was undermining them, but merely pointing out a flaw. And the flaw isn't fixed, but rather situational.