Absolutely. I'm not saying it's acceptable, only giving background. "I'm being blunt." "I'm just being honest". etc. These are not excuses for being an asshole. The same information can be shared without being an asshole about it. Being an asshole towards others publicly on the mailing list is just another form of bullying. If he wanted to be blunt or whatever, he could do it in private messages. There is no need to publicly shame people.