Higher frequency is definitely harder on the body as a whole, but specifically joint/ligaments/etc. I'm talking same muscle grouping 2-3 days a week and especially 4+ days. Volume may be reduced per training session, but total volume per week is still high (may be higher) and the intensity can still be fairly high. With that, the body is still in a fatigued state or recovers just enough to manage the next training session. This puts a lot of stress on the slower-to-recover joints, ligaments, and tendons.
Higher volume and lower frequency may feel "harder" but given the sheer volume of work targeted on a few select muscle groups, the intensity MUST be reduced to get necessary work complete OR the intensity and quality of work will naturally reduce because you can't go 100% or even 85% on every single one of those lifts (as listed in the example session). It will feel hard but a drain in energy/strength will keep you from really killing the joints. And if it does come to that, you'll probably have 6-7 days to recovery.