Notice the vastly differing responses between Slifkin and Rabbi Nosson Kamenetzky when the gedolim assured their books. Rabbi Kamenetzky also disagreed with the ban (even after it was issued) and said as much. But, nevertheless, he immediately withdrew his book from circulation and print. And he never once attacked the gedolim and even though he disagreed with them he followed their instruction vis-a-vis his book.
On the other hand, not only did Slifkin not follow the instructions of the gedolim, and instead tried to cobble together a few rabbis of notably lesser stature to back him, but he furthermore then went on the personal warpath against the gedolim who banned his book. Something that he continues prosecuting years later.