Pernicious to be vague and disingenuous to be opaque.

‘obscurity in a writer,’  ‘Empson (the poet) may be due  to a refusal to speak out’).

 It was pernicious to be vague, he implied, and disingenuous to be opaque.   

The writers whom he valued, and who crop up most often in these letters (Shakespeare, Marlowe, Herbert, Donne, Marvell, Fielding, Coleridge, Joyce, Orwell, Dylan Thomas), had in his view found ways to resist religious conformity 

(religion and politics for Empson are virtually inextricable from each other).

 They give voice to the personal conflicts of their times, not to their resolutions. But they do not endorse the prevailing views, nor do they require their readers to. 

Religions, with the possible exception of Buddhism, provide bad solutions to insoluble problems and, he sometimes intimates and often insists, it is the function of literature to expose this terrible fraud.