The GOP has gotten to where NO election is legitimate unless a Republican wins.

As to gerrymandering, as you noted, yes Democrats do it too. But an important distinction can be readily made from facts: That in states like Arizona and Michigan, which implemented non-partisan/bi-partisan districting commissions, it wasn't Democrats that tried to stop such commissions as the GOP did in both states. Here in Michigan, balanced districts actually put Democrats in full charge of the state legislature for the first time in FORTY YEARS! And with the re-election of our Democratic governor, we Democrats have a "trifecta" as ballotpedia calls it for the first time in forty years- both chambers of the legislature and the executive branch!

But as a Bernie Sanders voter, I have to partially blame the "stolen election" on my fellow progressives. They ranted stolen election so much in 20116 that it put that meme into play for Trump and his cult members! Indeed there were lots of issues and problems with the primary that year. Voter rolls purged in New York, conflict in Nevada, etc. But I kept telling people that they were taking 1+1+1 and arriving at 5.