[cycloptic]

You are of course welcome to have an opinion, and to choose whatever product you want based on that opinion. But if the extent of your opinion is "this person is a jerk and their work is terrible and not to my taste" that is unlikely to convince that person to change course, especially if they don't know you and if the decision is already made.

[scaramanga]

Furthermore, the "this person is a jerk" part is clearly not part of some dispassionate evaluation of his professional accomplishments and is just a verbal attack couched in the language of professional criticism.

I suspect that, in many instances, people who do that are not trying to convince anybody of anything. If they expected to be greeted everywhere with agreement then they would not go around saying things which they know perfectly well are not likely to result in a vigorous and healthy debate if they were said to strangers in the street :)