Katt Watson
I think this is less about counter-claims and more about how people discuss things logically. If a statement is posed as fact and posted in a relatively public forum then that statement is, by default, up for debate.
If a claim is made then evidence must be provided to support the claim, the evidence or examples used to support the claim are required to be veracious for the claim to stand and be given merit.
If the counter-claim is directly related to the original statement or "claim" and is also supported by the above conditions then it is relevant and should be taken as so and discussed as so.
Personal remarks, assumptions, comments irrelevant to the original statement and/or the direct counter or response and logical fallacies serve only as derailment and obfuscation and to greatly weaken the position held by the person exhibiting those behaviours.
I also disagree very strongly with posting personal or insulting comments then deleting them. People tend to notice things like that.