I'm pretty sure his point was that running in and of itself (outside of external factors such as other people on the road, etc.) is very detrimental to your health- specifically your knees.

Obviously doing any physical exercise you should be safe about it (wear a helmet while biking, have a light and reflectors if you ride at night, etc., and of course be conscious of your surroundings), but running solely by itself can be detrimental to your health because of the force you put on your knees on impact running on paved surfaces.

I assume that was his point. However it is not a given that running is "very detrimental to your health"; in fact that's a pretty bold claim to make without any evidence or indeed consideration of the health benefits. It's true that knee problems are a concern for some runners (and indeed participants in many other sports), and something frequent runners should be wary of.

"Barefoot" running is much easier on the knees. You land differently and thus avoid the sudden jolting stops.

Yes, I will agree that "barefoot" running is better on your knees than with standard running shoes- also running with proper form would be, but alas- almost no recreational runner will do either of these things, and it is especially hard to do so on typical running paths (such as, you know, roads).

Given the constraints of what we're given, biking is far better for your overall health than running.

I walked in to work this morning, during which time many runners passed me. None of the women--and most of them were women--were heel-strikers; from my past observations, few women are. And of the three men who passed close enough to see, all landed on the middle of the foot.

You don't need to run barefoot. Just tilt your foot forward and land on the ball rather than the heel. You can stick with regular running shoes and do this.