Honestly, making the assumption that because they overstayed due to a HO screw up that they'd get some consideration at application time doesn't strike me as all that outrageous.
But there's no consideration to be given. One of the problems with this debate is that there are two issues involved. One is the HO's mistake resulting in their not getting the CoA in time causing her to become an overstayer. The other is them complaining that she has to leave even though they're married. However, the fact is that she would ALWAYS have had to leave, even though they're married and even if the HO had been completely on the ball. Switching from a visitor visa to a spousal visa is not permitted. If they'd gotten their CoA on time, then the title of this thread would just be "Heartless Croydon PEO strikes again" and would feature the couple's heartbroken shock when their FLR(M) application was refused.
I do agree that there are mitigating circumstances surrounding the overstay, however it should be noted that they didn't even send their application for a CoA until a month before her visa ran out. That doesn't leave much of a margin for error of any description. What if the registry office had lost or misbooked their appointment? Would they, then, be "heartless?"
And as to judging others, I would agree that none of us is competent to judge this couple's characters or their intelligence or their morals. However, we are perfectly able to judge their
actions, or if not to "judge" per se, at least to "have an opinion on." And as Mort pointed out, in the absence of abundant facts, we are
all speculating, and speculating one way is no better or worse than speculating another. If people have opinions that you disagree with, that doesn't mean that they are "judging" and you are not.