I have respect for both Elizabeth Warren (my preferred candidate in 2020) and Bernie Sanders (my preferred candidate in the 2016 primary after Warren declined to run). I do believe something was said by Bernie in their 2018 meeting, possibly about strategy and how it would be difficult for a woman in 2020 against Trump and his unprecedented sexist attacks. Any comment would have been specific to a 2020 run against Trump, not a comment about women in general.
Bernie acknowledged in the debate that he held off running in 2016 in hopes that Warren would run, acknowledging her as the first choice for 2016. In the 2020 cycle, Warren announced weeks before Bernie did. She met with Bernie, who had held back in 2016 in deference to her run, so it was reasonable for her to expect his support.
Instead, it seems his male ego got too caught up in the adrenaline (and testosterone?) of his 2016 campaign.
I do not believe Bernie said a woman could not be elected president in general; there is video of him in 1988 saying a woman could be president and, again, he acknowledged his initial support for a 2016 Warren candidacy before Warren backed off (citing inadequate foreign policy experience, which she has subsequently developed).
I do believe something was said. Warren remembers it; Bernie is feeling defensive. Warren let it simmer for a long time, but when top, over-eager Bernie campaign operatives (I hope Bernie wasn’t directly involved) released talking points saying Warren appealed to elitists, then denied it, then admitted it, it got Warren riled up and she revealed something that has been a sore point since it happened.
It is another case of a man getting his ego worked up, then getting defensive, evasive and feeling entitled. But in this case, as Mitch McConnell learned, nevertheless Warren does persist, and she will stand up and speak up.
When it is “HE SAID vs SHE SAID” … BELIEVE THE WOMEN.