I haven't bothered to check whether these memes contain authentic quotations from the men whose photographs they use. What interests me here is that whether or not Tyson and Whedon said these things, some of their fans were happy to believe that they did.
this one probably was. I did find this article, which I haven't read in full yet but it doesn't contain the quotation from the meme. But again, what interests me is that it's popular among his fans, as something they agree with, so they take for granted that he must have said it.
Ignorance is not a virus, and reason won't "cure" it. Ignorance doesn't have to "spread," because it's an inescapable part of the human condition. What we know will always be limited, incomplete, and subject to revision, especially what we know about things much larger or smaller than human beings. We will always be ignorant about some things, and I believe that our ignorance will always be greater than our knowledge. The real problem, once again, is not that people are ignorant, it's that they know so much that isn't so.
I recognize that Tyson didn't mean "virus" or "cure" literally. That's the trouble. He's preaching, not sharing information. He's a revivalist, and he's highly selective in his use of reason. This meme is an altar call, the very opposite of reason. Tyson's language shows that he belongs to the ancient religious tradition which teaches that if your spiritual eyes are opened, if you are awakened and enlightened all error will immediately fall away. It isn't true, but a lot of people believe it, because they want to believe it; and of course it's very satisfying to believe that you are one of the enlightened elite, part of the cure, and the ignorant masses, with their myths and superstitions are the problem. If anything should be cast metaphorically as a malignant virus, it's that belief.
No one really knows what equality is anyway. Amartya Sen wrote a useful book on the subject, Inequality Reexamined (Harvard, 1995), which pointed out some of the conceptual problems involved, but Noam Chomsky did a good discussion as well.
Nor is equality like gravity, which is not really a "necessity" either. Gravity is a fact, but like equality no one really knows what it is either; scientists are still trying to figure that out. Like many basic realities, everybody knows what gravity is until they try to explain or describe it. Equality is different; rather like justice, or the Good, it refers to what isn't rather than what is. Its very vagueness is useful, since people can advocate it without having to think very hard about what they mean by it. But unlike equality, gravity is something that we needn't be bound by. Many species have found ways to get around it, and human beings tried to do the same for thousands of years. If we treated gravity the way Whedon wants us to treat equality, we'd reject the very idea of flight, let alone space travel. When we're trying to get off the surface of the earth, gravity is our (metaphorical) opponent.
Notice too how Whedon loses track of his pronouns and their antecedents. The "it" in "It is life out of balance" is presumably meant to refer to misogyny, but in context it points to "equality," which is not what Whedon means at all.
It appears that Whedon was talking about sexual/gender equality, though I suppose he didn't mean to exclude other areas. And I suppose he was extemporizing here, so it's unfair to blame him for getting lost on the way to his thought; but in that case it's unfair to put his ramblings into a meme and send them, naked and unprotected, into the lethal vacuum of the Intertoobz.
Memes like these are part of the reason I've been in a foul mood lately. I agree about the value of reason. I think that equality is important. But too many of the people who are nominally on my side on these issues are depressingly irrational. I can't blame them. I know the limits of my own rationality, and I know how hard it is to use reason, to ascertain facts, to talk about reality, to tell the truth. But the popularity of people like Tyson and Whedon (and even of people like Noam Chomsky, who knows this and tries to resist it) just reminds me that what many people want is a Champion they can cheer for in the great gladiatorial arena, our guy versus their guy. And it's largely accidental which side they're on.