GAW- but it does illustrate that disagreeing with one’s hashkafa, even with harsh-ish words, isnt sinas chinam. unless someone would have the gall to accuse R aharon ztl of sinas chinam. which would be pretty dumb.
Preaching to the choir. See The Milchamos talk about the Ba’al Hamor if you really want to see “Harsh words” (which I’m sure you already know).