Teaching as a job is precarious
Which affects what gets taught.
Most teaching is casual, paid per class, frequently dependent on attendance, and without preparation time, sick pay or continuity. Teachers commonly work across several studios to assemble an income, which means travel and no relationship with any single group.
This has direct consequences in the room. Payment dependent on numbers creates pressure toward the popular class rather than the appropriate one. Working across venues prevents the accumulated knowledge of individual students that makes teaching safer. And further training is self-funded on a low income.
It also means teachers are poorly positioned to refuse. A studio wanting a particular format, or a student wanting an adjustment they should not have, meets a teacher whose livelihood depends on being accommodating.
The studios that produce better teaching tend to be the ones that pay per class rather than per head, that pay for training, and that keep teachers with the same groups over time. Those are business decisions rather than philosophical ones.
The other consequence of precarious pay is that teachers have limited capacity to turn students away. Somebody who should not be in a general class, because of an injury or a condition, is a paying attendee, and declining them costs the teacher directly. That is a structural conflict rather than a failure of judgement.