If Deliberately Missing Mass Is A Mortal Sin, Then What Is This ?

[Blind Horus]

In other words, these heretics and false shepherds are encouraging mortal sin! 

Yee serpents, yee generation of vipers, How can yee escape the damnation of hell?

[cassini]

Isn't there an old expression along the lines of lower levels of Hell being paved with the skulls of bad bishops?

There is indeed dahhveed. I recall when first hearing this (La Salette?) thinking, 'how could anyone say such a thing.'
That was then, but not now. I always thought the holiest men in the world were priests, bishops and popes. But now, with modern means of communication all around the world, and my experience here in Ireland, I now know they are the greatest cowards on Earth, not doing what they should be doing, defending the Kingship of Christ against the secular world. But now that they are all caught up in sexual scandals, saying nothing, protecting those involved, spending Church money as though it was theirs, I cannot believe it. Here we are, trying to avoid hell by keeping the commandments as best we can, and they obviously don't even believe in hell.

[BobCatholic]

The road to hell is paved with the skulls of bishops.

I can see where one key source comes from: Germany.