Why can’t you say horrific things about gedolim if they did something wrong?
The RCA has an obligation to stand up for Torah. If someone acts in such a way that is creating a bizayon of the Torah, namely calling people evil, etc. then they have an obligation to stand up for that.
What about all the charedi rabbis calling Lipman and other DL folk names? Is that also forbidden or since it’s charedim, then it’s OK?
If ROY can call a rav evil, I see no reason why the RCA (or anyone) can’t call him on it.