I think you might have missed the point-- I don't think the poster you are responding to is actually endorsing the view that this video is fake, they're saying the skepticism applied to it would be useful more broadly.
The point that Guinness witnessed it and that Lars is well known are great ones-- but there are many things people believe unquestionably which don't have evidence anywhere near as strong as that.
The point that Guinness witnessed it and that Lars is well known are great ones-- but there are many things people believe unquestionably which don't have evidence anywhere near as strong as that.