As a swing voter, non-affiliated, basically non-partisan, I can't see anyone calling anyone in the Democratic Party as far right. I suppose if one is far left enough, then perhaps that could be done. Moderate Democrats, yes. As in Manchin, Sinema and how Biden used to be. This from someone who falls into the crack ideological wise in-between the two major parties. Some folks call us centrist, moderates but that not right either as a lot of in-betweeners will support the Republicans on some issues and oppose them on others, same for the Democrats, support them on some, oppose them on others.
Now you do have the establishment of both parties who rely on corporations, wall street firms, lobbyist, special interests, mega individual money donors, etc. to get their money for campaigns and to run their organizations. Most of those above will donate to both parties, but will give the majority of their money to the candidate and party they expect to win. But to be safe, they'll always give the challenger or the underdog money so if the underdog wins, the underdog will still owe them. But there's nothing right or left about this. The idea is to elect people, candidates who owe them.
Now in 2010 Lisa Murkowski lost to Tea Party candidate Joe Miller in the Republican Primary in Alaska. But then Murkowski beat Miller and whoever was her Democratic opponent as a write in candidate to keep her senate seat. So Buffalo isn't alone nor is the Democratic Party.
I had saved a couple of articles that pointed out that Hillary Clinton was decided on as the Democrats 2016 nominee back before the 2012 election in a secret meeting between Obama, Bill Clinton and Hillary Clinton. It's bed time per the wife, so I'll have to look up those articles later.