Cosby is a talented comedian, actor and educator, and his comments on how some Black people do dumb things like shoplift, riot and act out are entirely correct. His being a lech (as he is accused of being) does not make less talented or his comments less accurate. The fact that a person is an expert at one field does not make him a saint. Washington and Jefferson owned slaves, and perhaps Jefferson slept with a teenage Sally Hemmings in a situation that would be clearly child abuse today, and Sally seems to have borne his children. That does not mean that he was any less skilled at the many valuable and admirable things he did. The fact that a person has one or more character defects does not invalidate his qualities. I am pretty sure that Adolf Hitler was better at oil painting than I am. So was Dwight Eisenhower.
Summers might or might not be accurate in his theories about why there are so few women scientists and mathematicians. He has a right to have that opinion and to express it. But as Tyson says, to validate such a theory, we must first have a situation in society in which women have the same social attitudes towards their talents as men have. Until such time, there is not a valid scientific way to confirm his theory.
Neil DeGrasse Tyson is a brilliant and articulate scientist, and he is more brave that most about his beliefs. There are a lot of scientists that are atheists and do not dare to declare this publicly, as has Tyson. After having watched his version of "Cosmos", I think he did an even better job than did Carl Sagan. Of course, there have been scientific discoveries made in the intervening years about the size and age of the Universe that were unknown when Sagan produced his version. Sagan, being a scientist, would almost certainly agree that Tyson added to the value of the presentation, It is the nature of science to constantly add to the body of knowledge. And I do not mean to detract from the hundreds of people behind the scenes that contributed to make both versions of Cosmos so informative and enjoyable.
When I was in undergrad school at a Southern Baptist college in MO, the biology teacher, a Dr Gyer, dedicated one entire class to explaining his concept of the Theory of Evolution. His main example focused on how Parker fountain pens were superior to other brands that had gone before, and how this meant that Parker Fountain pens were sure to take over a larger share of the market, because they were easier to fill and held more ink and the nibs did not wear out so quickly. I assume that he dared not mention plants or dogs or God forbid, monkeys, chimps and humans, lest the preachers that served on the college Board of Trustees might get wind of him *gasp!*, being an evolutionist. The textbook for Bio 101 did mention DNA on about ten pages as I recall. There were nothing whatever on Dr. Gyer's exams or handouts about Natural Selection, Darwin or even fountain pens. Some scientists have more guts than others, and one has to respect that.