I am guessing that this was done out of necessity during the period of Soviet hegemony in eastern Europe, and that the canon was dispensed with.
Of course, but even if they were in violation of Canon Law ... so what? It wouldn't invalidate the episcopal consecration of such an individual, nor would it invalidate a papal election ... unless a prior Pope had set such a condition in one of those docuмents that lay down the requirements for the next election. If Pope Pius XII had written ... "if the man elected had not been a priest for at lest 5 years prior to the Conclave, the election is null and void", then it would be a problem. But there's no such condition, and it would not violate a valid consecration or valid papal election.
IMO, by far the biggest question is ... who were these "electors"? Now, it is true that papal election has its roots in the clergy (and faithful) of (the diocese of) Rome electing the Bishop of Rome, aka Pope, and that in the event of some breakdown where we have no Cardinals left (let's say they were having a Synod on Synodality and all got nuked), if there were any clergy of Rome left, they could elect a Pope, and that would be legitimate. Some say it would fall then to an Imperfect Council, but I don't know that I buy this. I believe it would be first clergy and faithful of Rome and THEN (if those were gone also) an Imperfect Council.
But some of the problems are ... who is a clergy or faithful of the Diocese of Rome? Is it any priest who happens to live in some (relatively-arbitrary) geographical boundary for the Diocese of Rome? What's to prevent carpet-baggers from coming in and influencing an election in that case? No, I would think that at least the clergy of Rome would have to be those who had been made clergy of Rome by the Bishop of Rome, incardinated into the Diocese ... which is actually what happens with Cardinals, where they are incardinated in a sense as "clergy of Rome" and then given titular churches in Rome. So the fact that the Popes have given them these titular churches suggests that the Tradition of clergy of Rome electing the bishop of Rome is almost certainly of Apostolic Tradition and Origin, and about as close as you could have to being Divine Law. Now, then, St. Robert Bellarmine hypothesizes that if all these were wiped out, an Imperfect Council could do it, since God would never leave the Church without a means to elect a new pope. In the early Church, it sometimes happened that the NEIGHBORING bishops of a vacant See would come in to set up a bishop, or else a metropolitan or major archbishop type might ... if there were some problem with the clergy in that area doing it themselves (e.g. they all went Arian or apostate). So that's where this would come in.
But let's posit that ...
1) the See of Rome is vacant
2) all the Cardinals are gone (either defected, or not legitimately appointed by Anti-Popes, or heretics who are therefore ineligible)
3) and there are 3 orthodox Catholic priests left who were priests of the Diocese
In such a scenario, I believe those 3 priests could elect the Pope validly, legitimately. If there were no orthodox priest left, I believe the faithful of Rome could then elect a Pope, and have a neighboring bishop come in to ordain/consecrate. But then the sticky thing there again is who are the faithful of Rome ... those "registered" in some canonical parish prior to the emergency scenario?
So I believe that Brother Bugnolo's principles are not entirely far-fetched. We're far removed here from Bawden's election in the cornfields of Kansas, with his parents and former girlfriend being the majority of the electors.
Problem ... (as per 1 to 3 above)
1) there's no universal agreement that the See of Rome is actually vacant ... as we have many R&R types and conservative Novus Ordites clinging to Prevost as legitimate Pope
2) it's likewise disputed whether all the Cardinals are non-Cardinals ... not only by R&R / conservative Novus Ordites, but you could add Sedeprivationists into the mix, where perhaps at least some of these Cardinals are legitimate and are not pertinacious heretics (such as, e.g., the Eastern Rite Cardinals)
3) if the See is vacant and the Cardinals illegitimate (which would clear the way for an election) ... then there would be no more priests/clergy of Rome left to elect a Pope
In other words, the conditions necessary for 1 and 2 above, would then preclude condition #3 from being able to happen. At that point, we'd need an Imperfect Council ... which we're not going to get barring divine intervention.
But if #2 isn't the case, and at least some of the Cardinals are legitimate, e.g. Eastern Rite ones who are valid bishops and not pertinacious heretics ... as Brother Bugnolo must certainly believe, since some of them go back to the Ratzinger era, AND Brother Bugnolo's previous conclave did elect Bergoglio at some point, making the Cardinals he appointed after that point legitimate also (in his mind) ... so if #2 isn't the case, then by what principle does #3 now come into play, as Brother Bugnolog claims?
He says that simply because the last Conclave was invalid, due to a violation of the Conclave rules (too many Cardinal electors) ... this somehow entitles the clergy and faithful or Rome to proceed with an election. Now, even that doesn't follow, since some theologians hold that a technically-invalid conclave would be sanated by a "Universal Acceptance". Now, while I don't agree with that, good luck convincing everyone that it isn't the case.
So given all these what-ifs, disagreements, etc. ... the confusion and fog around such a thing would render it impossible for such a Conclave (even if technically valid, where Bugnolo is correct about every conclusion he's made per the above) ... there would remain so much disagreement, non-acceptance, etc. ... that his Conclave could not produce anything more than a
papa dubius at best, meaning that we're still in the same boat and he's solved nothing.
Now, if he's right, perhaps God would provide miraculous signs of his having approved the election ... and win over the entire Catholic world, but even that's sketchy, as Clemente Dominguez had preternatural abilities also and the devil can fake miracles.
There's also a bit of a conundrum for Brother Bugnolo. According to his thesis, there was a time (before they elected him) that Bergoglio was not a valid Pope. That would mean that the Cardinals whom he appointed during that time period would not be legitimate, and that would put the total number of electors under the number specified ... and so the Conclave would not have been invalidated on those grounds. I'll look it up in a minute here, but I'm also certain that's the case.