Doesn’t it make the most sense to blame our election system that makes people feel like they don’t have enough choice or the ability to express their actual preference in an election?

The Democratic Party is a product of this flawed system. You can make things a bit better, but at the end of the day, you have to have a party that is a coalition of disparate groups that choose a single person who has to win it all. So, a candidate that super excites and energizes one faction of the coalition is likely to be very unappealing to other factions. And most of the time you’re going to end up with someone who nobody is actually excited for. It would be great if Democrats had a preferential/ranked voting system for determining that one candidate, which allowed for many candidates, and for those candidates to stay in the race without the risk of cannibalizing others (e.g. having both Warren and Bernie wouldn’t detract from either one). However, even this isn’t determined centrally by the party, as each state gets to do voting the way they want to. So, it’s not an easy problem to solve.