Just because a person in the past had been a scammer.... it does not mean this time round a person could be right. Ignoring a person 100% because of one's past is plainly stupid.
Whilst doing this would be somewhat fallacious, not doing it with certain individuals such as C.W. is unreasonable.
Let's suppose Craig told you your house is on fire... you ignore him... arrive home and whoops, house burnt down.
I'm absolutely sure that my house would not be in flames if C.W. told me that.
Anyway, you claim to have debunked it ages ago, but i was more concerned about the "This is one of several hundred attack scenarios which SegWit could open."
Would you "be concerned" about a high school kid telling you that there are "several hundred attack scenarios" in something that has been peer reviewed by dozens of engineers? This is pretty much it. C.W. is not competent enough to find a single attack scenario that someone else may have missed.
https://twitter.com/i/moments/877046701474721793