Emails that should not be sent

Dear X,
Regard­ing your com­ment dur­ing our recent phone con­ver­sa­tion.
In this con­ver­sa­tion I said some­thing like:
“I must have missed the update.”
And you replied with:
“That hap­pens a lot at [my depart­ment].”
I find your com­ment to be extreme­ly unpro­fes­sion­al, and more than that, to be unnec­es­sary and unciv­il.
The whole point of send­ing out the final con­fir­ma­tion is as a dou­ble check, last chance error cor­rec­tion process.
The issue of the wrong room hav­ing been list­ed was very minor and cor­rect­ed com­plete­ly with­in the space of the short phone con­ver­sa­tion.
Why was it nec­es­sary to take such a cheap shot at me per­son­al­ly and [my depart­ment] as a whole?
Your com­ment was inflam­ma­to­ry, and divi­sive.
Do you suf­fer the self-delu­sion that you and your depart­ment have nev­er made any errors?
Please refrain from such bul­ly­ing tac­tics in future.
Kind regards.