In this bad astronomer video, Phil Plait says two things:
1) He first demonstrates the effect of gravity using paper, and he keeps a fixed mass and distance. However as he makes the paper smaller and smaller keeping the mass the same, he says that the particle can get more closer than before, or gravity increases. However, towards the end of the video, he says that the star before collapsing has a mass of 20-40 times the mass of the sun, but once it does, it reduces to 3-4 times. But in this example he is changing the mass for two different situations. How does this fit in with the crushed paper analogy?
2) Again, towards the end of the video, he says that if the sun were to become a black hole, the Earth would continue orbiting as usual because it experiences the same gravitational force as before. So if there is no change in the gravitational pull what makes the sun a black hole? Just the fact that it is the core of a collapsed star?
And using the above example of the sun becoming a black hole, when does a black hole actually start "sucking" things into it?