Hotly as the faddists ...

Hi

An owner of a private school is talking to a new teacher and he tells her:

Inside the classroom, all but the very
dullest will speak and write with some regard for grammar;
outside, all but the very exceptional revert to the
vernacular. You mustn’t let that depress you. It’s just a fact
that must be faced: hotly as the faddists would deny it, at
least three-quarters of all compulsory education leads to
nothing at all.

--- I don't get the part: hotly as the faddists would deny it ...

Does it maybe say: It's just a fact that must be faced and many faddists would hotly deny it, but at least three quarters of all compulsory education leads to nothing at all.

Do I understand it correctly?