Non-copyleft licenses are shortsighted, they ignore what happens after. The code may be open at the moment it's being shared, but it won't stay open in the future if you don't plan for it. That's what copyleft does.

I find it fascinating that some people's definition of freedom is so narrow as to completely ignore consequences. It's like saying "I'm more free than the average person because unlike them I can step out this window and fly for 2 seconds". Great, but then what?