I know this is the age of oversharing, but just because something is from a perspective doesn't mean that people should be interested in it, or that is wise or fair to share. Making it specific and detailed is a way to make it fairer and more productive.
edit: also, to appeal to self-interest, people respond to detailed argument with attacks on the supports of that argument. People respond to vague accusations with ad hominem (which may be very specific) because there's no argument to attack. Vague accusations are almost always eventually more damaging to the accuser than to the accused.
That doesn't mean brushing it off though. More of a vent to cool yourself off before taking the next action. At least that's what I've always done.
At least you can somewhat "un-say" things now a days if you control the content hosting.
Yes unsubstantiated claims can be harmful, but that doesn’t mean that no such claims should ever be made. The author is not just bad mouthing their research group, but presenting their perspective of what took place.