"For much of last year, this site advocated a rational but unpopular position – namely that the SNP, which at the time held the balance of power in the UK parliament, should offer to support Theresa May’s soft-Brexit deal in exchange for the transfer of powers to hold a second independence referendum."
What's wrong with that sentence? Well, where to begin. First of all, the SNP didn't hold the balance of power in the UK parliament - if that had been the case, Jeremy Corbyn would have been Prime Minister, not Theresa May. Secondly, the position Wings advocated was not "rational but unpopular" - it was in fact popular (with Wings readers) but irrational. Yes, the SNP could have made Theresa May an offer, but it would have achieved absolutely nothing. Her reply would have been -
"Our Precious United Kingdom is not for sale. We do not do deals with separatists."
You might argue that would have made her crazy when somebody was trying to save her bacon, but nevertheless it's indisputably what she would have said. And actually from her own point of view it would have made perfect sense, because the SNP weren't in a position to deliver the deal anyway. They didn't have enough votes to put the matter beyond dispute, and more to the point some of the Tory MPs who voted for the deal would have immediately swung the other way if they knew that "the precious" was at stake.
So by all means criticise the SNP for not doing the things they could have done to bring about independence or a choice on independence. But don't criticise them for not attempting something that was never in their power, and that would have simply have left them looking a bit foolish, a bit cynical, and above all else strategically naive.