Dr.Johnson was our great man of letters when he said "stinks," not when he said "putrefaction." Take some common phrase like "raining cats and dogs," and note not only the extravagance of imagery (though that is very Shakespearean), but a jagged energy in the very spelling.

Say "chats" and "chiens" and it is not the same.
Perhaps the old national genius has survived the urban enslavement most spiritedly in our comic songs, admired by all men of travel and continental culture, by Mr.George Moore as by Mr.Belloc.One (to which I am much attached) had a chorus-- "O wind from the South Blow mud in the mouth Of Jane, Jane, Jane." Note, again, not only the tremendous vision of clinging soils carried skywards in the tornado, but also the suitability of the mere sounds.
Say "bone" and "bouche" for mud and mouth and it is not the same.
Cobbett was a wind from the South; and if he occasionally seemed to stop his enemies' mouths with mud, it was the real soil of South England.
And as his seemingly mad language is very literary, so his seemingly mad meaning is very historical.

Modern people do not understand him because they do not understand the difference between exaggerating a truth and exaggerating a lie.

He did exaggerate, but what he knew, not what he did not know.

He only appears paradoxical because he upheld tradition against fashion.