Serious criticism serves two legitimate purposes: it helps audiences avoid meretricious wastes of time, and it holds artists to high standards. Serious critics strive to be useful; they want to earn the trust of audiences and the respect of artists. So they don't merely snipe.
A person who merely expresses antipathy toward a work of art, or toward any individual contributor to it, is not a serious critic, and merits little or no attention. Expressions of antipathy neither educate nor inspire, and when tinged by animus they harm rather than help others.