To an extent that's a fault in the leadership, and in one branch of Christianity I think much of it goes back a generation, maybe two, to a time when the hierarchy realized seminaries were producing priests whose understanding of doctrine was inversely proportional to their confidence in it. Rather than addressing that head on they chose to reorder the seminaries to produce priests with unshakable belief in official doctrine--even though that required them to be largely ignorant of said doctrine since they'd ignored the deeper problem. Ultimately though the onus is on the laity to read their bibles, pray and work out their salvation with fear and trembling. Unfortunately, many do such a poor job of this that it's possible for a man to state that last quote as "work out your kingdom with fear and trembling" and get away with making it part of a whole new religion.

So, yeah, he's not wrong, but you're definitely right. We're all sinners according to Christian doctrine, so no one can claim any superiority there: I came up short just like everyone else. However, just as there was no way to know at birth that I'd come to Christ and let Him bear my guilt there's no way of knowing that about anyone else, and it would be INCREDIBLY presumptuous of me to assume they're just hopeless doomed sinners. I'm certainly grateful a whole lot of people (starting with the Son of God Who died for me, in obedience to my Father) didn't do that to me.