I dont think either of the posted articles are doing lsd type rides, in a zone equal to recovery rides.

Zone 1 65% of MHR (recovery rides)
Zone 2 65-72% of MHR (endurance events)
Zone 3 73-80% of MHR (high level aerobic activity)
Zone 4 84-90% of MHR (lactate threshold(LT,AT); time trialing)
Zone 5 91-100% of MHR (sprints and anaerobic training

Thats usually what i see listed as 'zones'.
Recovery is at 65%, the lsd type rides you refer to are slightly above recovery in the 70% range.
Both the above articles appear to me to be promoting the 73-80% range, or high aerobic.

Both articles seem to be promoting long endurance training just below lactate threshold. As opposed to going full out and blowing up. Didnt see any reference to going 'slow'. But i do agree that the LSD type rides suck time away from you