EDIT: Present your valid complaint with civility
We are never allowed to justify abusive behavior because we believe that we were abused.
We are only allowed to present our case.
And, even then, do so in a matter-of-fact manner using quantitative language.
We cannot be condescending - using qualitative verbiage - raise our voice, curse
or dominate the conversation such that the other person doesn't get to reply to each and every point we make.
And if they do any of that, our only option becomes our choice to leave that which is a consensual exchange of information.
Because, after all, conversations are a choice.