That may be true, but it is an ad hominem argument that is irrelevant to the merits of what Fowler actually says, and without giving evidence it is unsubstantiated to boot.
That’s why a second edition was produced, in 1968. This edition was revised by Sir Ernest Gowers (I mistakenly omitted that in my cite), who is famous as a proponent of plain writing (he is the author of The Complete Plain Words).
None of this precludes the use of all concepts taken from Latin when discussing English. In fact, in the very alt.english.usage article Maeglin quoted from, which was “It’s me” vs “It is I”, the word ‘accusative’ is used five times to aid the discussion (the article argues that “is” does not always take the accusative case, but requires an agreement of case – Nominative takes nominative and accusative takes accusative).
Accusative case is certainly alive and well, even if we don’t always recognise its use.
