Dai has started a thread about football and Swansea City in particular and there are no insults in it, so therefore it is perfectly valid and should not be deleted.
The fact that he seems to be in a minority of one should, strictly speaking, be irrelevant.
To the vast majority of us, his left-field views are completely IRRATIONAL but none the less if they are his OPINION he has every right to post it. If the thread were posted by a QPR fan, for example, it would be a clear WUM and should be deleted but as Dai is a long-standing supporter of Swansea City (we assume) and a long-standing member of this forum it has to be left for all to read (if they choose).
To be fair, the title of his thread tells you what the content is going to be. If, as a group, we don't want to encourage him, the best thing to do is not reply to his thread or even read it in the first place.
I have read it. It contained everything I expected it to contain and in my OPINION, his OPINION is bonkers and I didn't respond.
Dai does have a problem 'debating' in the conventional sense and this can be frustrating - he either won't or can't, but we're all different so we'll have to accept it.