Henry VI was not a wicked man - though I think the pressure group that's trying to have him made a saint is pushing it a bit far. (He could be vindictive, especially if he he felt he was the butt of personal criticism, and he seems to have had a fairly obsessive belief that people were trying to kill him.)
His main faults were connected with his ability to do the job of king. He was a splendid example of the failure of the hereditary principle, lacking both the political skills of his English grandfather and the military qualities of Henry V. He was, in fact, rather ordinary. Had he been a bricklayer it wouldn't have mattered that much - though he might have been thrown out of his gild for incompetence. If he'd been a country gentleman, he'd probably have ruined his family fortunes, but there'd have been no wider implications. As a sovereign, he was a disaster waiting to happen.
In fairness to Henry, it would have required an exceptional talent to steer England through the mid fifteenth century. Parliament was already growing reluctant to fund the French wars in the closing years of Henry V's reign, and the government's financial position went from bad to worse as Henry VI's reign continued. Henry V's conquest (which never amounted to more than a third of France at best) was only possible because the French had been divided among themselves. Once some sort of national unity and confidence was restored a reversal of the situation was inevitable. Henry VI's government inevitably got the blame for this, but it's hard to imagine a medieval sovereign who could have done much better - given the finances allowed.
The other main problem of the reign was political and social disorder. This was of course partly related to the French Question and the related financial mess, but nonetheless it needed sorting and Henry was hopelessly ill-equipped to solve the problem.
Morally speaking there was little to choose between the various political factions that arose. While some had better rhetoric than others, they were all violent and self-seeking in the last analysis. Henry was unable to rise above this battleground and act as an objective judge of the quarrels. Instead he backed his favourites, time and again, seemingly blind to the defects of these men or the hatred he was building against himself.
The 'opposition' eventually came to realise that there was no justice to be had from the King, and they had to turn to violence or be destroyed. York (probably the least bad and certainly the least incompetent of the great lords) was rejected and politically isolated because of Henry's (initially irrational) suspicion of him.
It was bound to end in tears - and it did.