So, when I was visiting the seminary, I told Bishop Williamson that I was rather intimidated about entering the seminary after having read St. Alphonsus' book. Bishop Williamson explained that St. Alphonsus' audience tended to be the bad or lukewarm priests, and there's a bit of hyperbole there where he focuses on the ideal but not necessarily on the reality of our human weakness. Similarly, in other books, St. Alphonsus could have the effect of scaring people out of their wits, by citing stories about how young people just commit one mortal sin out of weakness, and a devil pops out from behind a bush to kill them and take them to hell ... but these stories are meant to scare the lukewarm and presumptuous (who constituted the vast majority, and were his target audience for the books). Otherwise, if one doesn't take what he wrote with that "grain of salt,", one might get a picture of God as being some ruthless unmerciful tyrant, just LOOKING to send people to Hell. Then, of course, in other books, St. Alphonsus will emphasize God's Mercy ... so that some of his books are "bad cop" and others "good cop". Bishop Williamson told me to take his writing with those grains of salt.
It's just the reality of human nature that most being on their path towards salvation through fear (and self-interest), and so he tries to scare these types to get moving.
St. Alphonsus isn't distorting or "lying" per se ... but it's more an example of emphasis. He's absolutely correct that absolutely no human being is worthy of the priesthood ... except there's the pesky reality (and Our Lord's concession to it) that the Church and we faithful need priests.
At the same time, the priests themselves CAN in fact be tended to think of them too highly, and I'm sure that the devil brings down many of them because they consider themselves big shots, as lay people bow their heads in reverence when greeting them and calling them father. So St. Alphonsus' books can help put them on guard against this type of temptation.
Priests have to understand that God did not call them to be priests because they're so great, so holy, so wonderful ... or in anyway deserving of the dignity, since in reality no one is worthy. God only called them for the sake of the faithful. They are called to serve and not to BE served.