[Reach]

Training 6 days a week is fine if you're not going heavy 6 days a week.

Going heavy 6 days a week is not fucking sustainable if you're natty, though, is probably his only point. I've tried it. You cannot physically recover fast enough without dropping the weight and sets, which impedes progress.

The only remotely sustainable way of doing this is literally a complete bodypart split where each of the 6 days is a different muscle group, but even then you'll burn out eventually as the weights start going up and could probably get more progress going to the gym far less.