This happens:

Two people agree on rules for communication - for example, either one can request a pause because they are finding it too distressing (a "boundary"), or they agree not to speak if it is becoming hostile or the bad kind of confrontational.

Then one person says they need to stop speaking because of the above conditions being present as they had agreed - and the other person accuses them of being "controlling".

Unilateral control or the perception thereof is incompatible with collaboration.

Mutual control, consensus or co-regulation is compatible with, and required for, collaboration.