Michael and Kegan discuss the general frustration with people who believe they are training Zone 2 but aren't. Aerobic foundation-building sessions that are programmed by the ignorant perpetuate the lack of results and such failure is masked by cheerleading. They bemoan the “influencer” propagation that simply being on a bike or exercise equipment is Z2, and also clarify that training endurance is not an afterthought or something that you get from by merely redescribing your shitty efforts as something more “official.” 

They discuss using proper (accurate) language to describe aerobic training sessions in the gym and the expectations associated with it; you're not trying to get it over with you are trying to extend it.

The lessons from those who have accomplished much and continue to progress in their endurance usually come to this conclusion: It's not about the time but about what happens within the time, the quality of the work is important (in this case quality is about attention, not speed). If you want to get better then you need to make the time to get better.

They conclude by remarking how gym culture is in contradistinction to building endurance (punish vs reward) and how sometimes the benefit from both is simply seeing the contrast in how each develops.