One should not flagrantly attack legitimate criticism.
Tips
usage
横加 always premodifies a verb of unwarranted action: 横加干涉 (wantonly interfere), 横加指责 (groundlessly accuse), 横加阻挠 (obstruct without cause). The 横 here means 'unreasonable, perverse', not 'horizontal' (héng → hèng in some readings; 横加 stays héng).