“Above all, he has to form his ideas without the aid of the purifying ordeal of skilled argument on the specific facts of a contested case.” [Citations below]
Judges are fallible. It’s not always entirely the judge’s fault. Cases aren’t always presented the way the judge, or somebody even more on the outside, thinks the case ought to have been.
And, sometimes the judge gets caught in the “purifying ordeal of skilled argument”: see, Heward v. Eli Lilly & Company, 2007 CanLII 2651 at paras. 25-26 (Ont. S.C.J); Commerzbank Ag v Price-Jones,  EWCA Civ 1663 at para. 48 (Eng. C.A.); and Cordell v. Second Clanfield Properties Ltd.,  2 Ch. 9 at 16 (Ch. D.).
The aphorism, as used in the cases I quoted, wasn’t a reference to the abilities of counsel. It was about the relative merits of judicial decision making versus academic scholarship. I’ll quote the passage as it appears in Eli Lilly:
 Prior to Serhan, the general principles governing waiver of tort had received little attention in Canadian courts. They have, however, been discussed at length by academics and other commentators whose views were referred to, and discussed, by Epstein J. in the Divisional Court. In attempting to formulate coherent principles that would explain and rationalise past decisions to accommodate the relatively recent recognition of a general law of restitution, there is no doubt that the learned commentators have greatly contributed to, and will quite properly continue to influence, its development. However, as the reasons of Epstein J. indicate, their views have not been uniform despite the enviable degree of confidence with which they have sometimes been asserted. This fact and, in the absence of binding authority, the level of abstraction and generality involved in the academic exercise underlines the importance of the caution expressed by Megarry J. in Cordell v. Second Clanfield Properties Ltd.,  2 Ch. 9 (Ch. D.), at page 16:
The process of authorship is entirely different from that of judicial decision. The author, no doubt, has the benefit of a broader and comprehensive survey of his chosen subject as a whole, together with a lengthy period of gestation, and intermittent opportunities for reconsideration. But he is exposed to the peril of yielding to preconceptions, and he lacks the advantage of that impact and sharpening of focus which the detailed facts of a particular case bring to the judge. Above all, he has to form his ideas without the aid of the purifying ordeal of skilled argument on the specific facts of a contested case.
 The words of the learned judge are even more appropriate in a case like this where, as in Serhan, the principles governing waiver of tort are relevant only for the limited purpose of determining, on a motion, whether the requirements of … [the Ontario class action certification statute] are satisfied.
[Words in brackets added.]
The U.K. judges who made the point were accustomed to a smaller class of full-time litigators because of the U.K. split bar. There’s room to argue that use that all three judges made of the aphorism was, at best, overstated; at worst, wrong. (Some might consider it ironic that the Ontario judge was, before his appointment, a full-time law professor.
But, sometimes, the advocacy wasn’t as skilled as it ought to have been, or might have been, for any number of reasons – not always the responsibility of counsel or judge – so the ordeal is just an ordeal.
The litigation process is, quite often, nasty and brutish, regardless of whether it’s short.