Yeah sounds like your mom isnt very good at handling these kinds of discussions.
Anyway, when you said you hate when x is rude - to me, thats saying something about an aftereffect thats TOO far down the line. Its like saying you hate that the global ice caps are melting when really somebody forgot to turn off the lights again.
Maybe if you had said to your mom, gee that whole thing this morning kinda upset the whole household, i still feel on edge, can i have a hug? (Or a cookie! I originally wrote cookie.

) Then you address what is REALLY going on, your mom doesnt feel like she has to choose who is right (was x rude or not?).