"...a nasty email..."
"Nastiness" can be in the eye of the beholder. Written words, casually or carelessly composed, can be prone to a perception of "nastiness" which a composer had no intent to express. Some folks just don't cotton to being corrected no matter how gentile the provision.
Not saying that's the case here but, without provision of a quote, there's no basis by which to determine whether your "vent" has some legitimacy...nor would it be productive to argue the legitimacy of your personal perception anyway.
Bottom line, if you're inclined to provide what might be perceived as corrective info to another member, don't be surprised if it goes unacknowledged, ignored or even elicits negative feedback. Everyone is wired differently.