I'm observing someone else's position

My observations do not yield the same results as yours.

seems to mean

How can you tell? Usually the question just isn't brought up. I mean, usually what happens is that someone says "isn't it unfair for people to be damned on account of mere ignorance?" and someone else responds: yeah, it would be, but actually that doesn't happen because those people will be judged in some unknown fashion according to their consciences. And generally the details of exactly how that works are acknowledged to be unknown, so there's not much more to say.

But for what it's worth, the nearest thing to a statement of this idea in the actual Bible, which comes in the Letter to the Romans, says this:

They show that what the law requires is written on their hearts, to which their own conscience also bears witness; and their conflicting thoughts will accuse or perhaps excuse them

(emphasis mine) which you will notice has "accuse" as well as "excuse".

This doesn't explicitly address the question of what happens if that conscience is bearing false witness and the wrong law is written in their hearts; again, that question tends not to come up in these discussions.

Just replace "Hell" with "Hell or Purgatory"

But doing so completely breaks your criticism, doesn't it? Because Purgatory comes in degrees, or at least in variable terms, and falls far short of hell in awfulness. So, in those Christians' view, God has a wide range of punishments available that are much milder than eternal damnation. (Though some believers in Purgatory would claim it isn't exactly punishment.)

I have also heard, from Protestants, the idea that although you can escape damnation no matter how wicked a life you lead and attain eternal felicity, there may be different degrees of that eternal felicity on offer. So it isn't only Catholics who have possible sanctions for bad behaviour even for the saved.

(This seems like a good point at which to reiterate that although I'm kinda-sorta defending Christians here, I happen not to be among their number and think what most of them say about salvation and damnation is horrible morally, incoherent logically, or both.)