Exclusively, no, but primarily, certainly. The number of R states with gerrymandering is numerous, while there are a few D states that do it. Further, and quite notably, the Dems in Congress are trying to pass laws to limit gerrymandering. Republicans have never done such, and openly want to allow it. And of course the Republicans are trying to cheat. WTH?! We just got through a prime example of that very thing from November through January. Is your memory really that poor?
As for "secession", the only reason we need it or should have it is because you and other tools believe in an alternative reality designed to divide us. As if we should be separating apart over six Dr. Suess books no longer being published. Idiotic.