There are a number of factually wrong statements in your post. The first is that a majority of Republicans don’t support Trump. This is wrong. Here’s a Qunnipiac poll https://poll.qu.edu/poll-release?releaseid=3825

This poll could be an accurate, but not completely inaccurate.

Another piece that is factually wrong is that “the left” was doing the same thing as oh what a majority of the Republican Party is doing now in reference to the 2020 election.

Donald Trump says the election was stolen. Hillary Clinton conceded the election. More than 100 Republicans running for office this November say the election was stolen. No Democrats running for office in 2018 or no, say the 2016 election was stolen. There were no riots and after the 2016 election. There were no people killed protesting the 2016 election. There was no attempt by Democrats to overturn the 2016 election. All of these things were and are happening by Republicans now.