The reason I think specifying people by name would have been OK is that 1 - they were presumably an issue for a number of attendees due to (prior) publicly stated positions and 2 - they apparently made subsequent statements via "broadcast" media such as Twitter, for anyone to peruse. This would be quite different if the people were more private, and if all discussions had been private and/or via non-broadcast tools like SMS or WhatsApp. Plus naming names could cause me to read what they had said and even disagree with the OP, at least on the baseline of non-inviting them. However the anonymity made the post much more interesting.