Tyson on Vera Rubin: Sexist, strategic, or simply friendly?

Tonight we watched the finale of Neil deGrasse Tyson’s Cosmos. The script seems to be carefully crafted, so during the discussion of dark matter, I wondered why Fritz Zwicky was usually referred to as “Zwicky,” while Vera Rubin was usually called “Vera.” Throughout the series they take great pains to include female scientists and thinkers, so was this a sexist oversight, referring to Dr. Rubin less formally than to Dr. Zwicky? Or was it a deliberate anti-sexist tactic, to keep it fresh in our minds that Rubin is female?

J. has another theory. It is very likely that Tyson knows Rubin personally, so maybe he was speaking with the intimacy of friendship, referring to her in the way he found most natural. I’m still sitting here wondering, though.