Prior to about 20 years ago there were no satellites looking for this stuff so we didn't see it. And the last time anyone saw it was when humans were crossing the Bering land bridge 10,000 years ago or more. Thus the statement is true, but not in the manner they imply. But it is a pretty good dramatic lie, isn't it?
Yup. Lots of things “appear” to be worse now due to the instant news cycle. Things we find out now would never have been heard across the country a couple of decades ago. As far as the land bridge, just “native Americans” returning from central Asia. Or something. :-)