Who would be influenced by mainstream Rabbonim speaking out against the protests?
For those in the Peleg themselves, they obviously won’t listen to Rabbonim from the “Misyavnim” camp.
For those in the mainstream, they are firmly against the protests (and protesters) anyway.
So it theoretically would only influence those “on the fence”.
The thing is, there are very few who aren’t firmly on one side or the other. (That is the nature of the land, you are either black or white. The question always is, which is black and which is white…)
On the other hand speaking out publically against them has many problems.
- A public dispute between Gedolim is a huge Chilul Hashem; even larger than the protests themselves. There is nothing more important than minimizing Chilul Hashem.
Disruptive protests in Israel are pretty common. The invalids protests are sometimes more disruptive than the Peleg ones – they just have understandably way more sympathy for their cause. - Harav Shmuel Auerbach Shlit’a is a tremendous Talmid Chochom and Yarei Shamayim. There is no real dispute about that. Coming out publicly directly against him can therefore only be done for a desperate need, and even then, with a tremendous amount of thought and subtlety; taking care to minimize as much as possible the Bizayaon of a Talmid Chochom.
- Coming out publically against the protests, in a way acknowledges that there is another side that is large enough to require acknowledgement, and that there is really an internal Machlokes within the Torah world. The Rabbonim in Eretz Yisroel have always tried to avoid this.