A teaching assistant should have 2 main responsibilities

1. To assist the primary teacher in any task that is required of them

2. To observe and record the behavior and development of students

I'd imagine that a lot of the said teaching assistants employed by Shane are still studying at Uni or have recently graduated. Furthermore they will have no formal teaching qualifications or experience. If i (a qualified/experienced teacher) were put in the position of being observed by a TA, I might well feel obliged to ask just who are you to provide feedback on my lessons?

Furthermore, as you've stated in your post there is a clear division in management between local staff including teaching assistants and foreign staff. So having 'observed' a foreign teacher's class who are the teaching assistants giving their feedback to? From what you've written i'd guess that they give the feedback to Chinese management i.e. the Sales & Marketing department. Again, i might feel obliged to ask these non-academic focused managers exactly who they are to provide helpful critique of my lesson?

Having this kind of organisation whereby teachers feel they are being observed and criticized in a non-productive way will make many teachers question whether they want to work in such an environment. The fact that the management at Shane Kunming doesn't understand this does, as the OP stated, show a lack of empathy on their part.