The fact that Democrat's managed on convincing you that Republicans gerrymander and they don't is a sign of how well their propaganda machine (aka MSM) works. Both sides do when they can get away with it, and kvetch when the other side does.
Just happens to be that recently (2010, and to a lesser extent 2020) Republicans were in control of more states.
Oh boy, where to begin. First of all, I didn't say what you're insinuating. I said D party messaging is that gerrymandering is bad, and therefore they have to contend with that when attempting their own gerrymandering. Second of all, while of course both sides it do, it's bad for democracy (no matter who is doing it), and it just so happens that the R's are currently gaining more advantage by gerrymandering (due to control of more states as you mentioned, as well as a more aggressive/coordinated effort at taking advantage of state control - see
REDMAP), so the D's are fighting it - see
HR1 - even as they continue to use it where they can.