Ex-teacher here. It isn’t all about your son. She was dealing with another incident. She quite rightly prioritised the other children’s incident and managed this by removing your son as he was providing an inappropriate and rude distraction.
As a parent, you need to ask yourself:
a) why is my child behaving so inappropriately in the first place?
b) why my child, at the age of 7 , is not yet able to follow a simple two part instruction “Go outside, and wait,”? We’d expect to see understanding at this level in EYFS.
c)what can I, as his mother, do to address the situation, that actually takes responsibility, rather than minimising and deflecting the problem onto his new teacher. (You didn’t say why he had so recently needed to move).
You haven’t mentioned any SEN, so I am presuming this has not been considered. Please consider it. His behaviour is not age appropriate.
Also, ask yourself if you are consistent at home. Are you consistent with routine, expectations, consequences, time and affection? Are you calm, patient and understanding, yet firm with your boundaries, as your child learns about his world? Do you spend quality time with him, absorbing yourself into the things he enjoys to do?
Not all of the children we see who behave like your son have SEND, some are literally crying out for attention, and have learned a really effective way to get it, by acting out. Attachment issues and the trauma children feel because of them are rife, and (in my anecdotal opinion) getting worse.