No. She's not only completely wrong, but seems to be playing the pity card in order to help her out of a gigantic campaign hole.
Hilary Clinton won the Democratic primary. She won the popular vote. She won the most contests. She won the most delegates, even if you factor out the super delegates. Don't get me wrong, I am not a Clinton fan. I didn't vote for her in 2016 and think she's worse than Trump. But it's a real stretch to argue that the DNC rigged it against St. Bernard.
As for 2020 election, the DNC/Tom Perez have every right in the world to formulate their own rules. It's their debates. They get to determine who they want to take and who they want to exclude. Perez made the rules very transparent and gave the candidates more options, more opportunities to get onto the debate stage. In fact, under traditional debate rules/qualifications, Gabbard would have never qualified for the June and July debates period. She would have been a maybe for the September debate. The reason is simple: she's a 1% or below candidate. You average together the major national polls, you will see she received anywhere between .5%-1% of the vote.
I believe Perez had the right idea: Set the bar extremely low in the beginning, and then gradually raise it.
Of course, the question becomes, how should candidates qualify for the debates? The DNC is not running a charity. They want people to hear from candidates, people actually want to hear talking. If you cannot make any type of dent in the polls, I am not sure why you should be on the debate stage.