To perpetuate the myth that Jill Stein cost Hillary the 2016 election requires completely ignoring the fact that two Republicans ran 3rd party that year as well: Gary Johnson and Evan McMullin.

If you are going to count Jill Stein votes as Hillary votes, then you have to count Johnson and McMullin votes as Trump votes. When you do that, Trump would win the 2016 popular vote by 895,428 votes.

But this is never done by Dems. They ignore Johnson and McMullin to favor a narrative that leftist/progressives tossed the election to
Trump by voting for Stein. The logic is flawed

This flawed logic also ignores the reality that many 3rd party voters on either side may have otherwise just stayed home had there not been a 3rd party candidate that represented their views and values. That would have added these voters into the large pool of non-voters for 2016

Approximately 100 million eligible voters did stay home in 2016, representing about 43 percent of the eligible vote, representing a far higher percentage of voters that voted for either Clintom or Trump.

Hillary lost by razor thin margins in a few key states, giving Trump the electoral victory that year. Which raises the quesrion: why couldn't the Democratic candidate inspire more non-voters to vote for her, thereby giving her the electoral win?

An NYT interview with black voters in Milwaukee immediately after Trump's electoral victory showed a deep schism between the Democratic Party and traditionally dependable Democratic Party voting blocks.

A black voter interviewed for this piece summed it up this way: "Both of them were terrible. They don't do anything for us anyway". https://www.nytimes.com/2016/11/21/us/many-in-milwaukee-neighborhood-didnt-vote-and-dont-regret-it.html

Until the Dem Party abandons the false narrative that 3rd party voters were responsible for a Clinton loss and starts asking the hard questions re: why traditionally Dem voters stayed home, we will never get anywhere.

Unfortunately, Dems spent the past 4 years blaming Russian influence in addition to Jill Stein as the reasons their candidate lost.

Focusing on these narratives guaranteed there'd be no serious consideration how a lack of a progressive platform that spoke to the needs of the growing base of disenfranchised voters contributed to the loss of a race that could have been easily won.

The implications for 2020 are serious, for instance, the current DNC platform's stance on health care is actually to the right of the 2016 platform. Specifically, lowering Medicare eligibility only to age 60, as opposed to age 55.

In addition, a complete abandonment of Medicare for All, despite almost 9 in 10 Dem voters saying they support it, represents a true disregard for policy positions that might bring in non-voters, whose numbers are growing, not shrinking.

To sum up, it is clear that having scapegoats like Jill Stein serves the interests of those who do not want popularly supported progressive change very well. These are the party leaders who will continue to risk losing elections rather than alienate their donors.

Democratic representatives, like their GOP counterparts, become very wealthy during and after their government service. Their aides also do once they leave government. Lobbyists and corporate connections are the key to this wealth.

These reps would rather continue to peddle false narratives on why they continue to lose than actually challenge the donor class which enriches them. When you look at government through this lens, the lens of self-enrichment at all costs, everything else falls into place.