Exploitative is the key word here. It suggests that while you are free to be as sexually miserable as you like, the moment you exchange hard cash for a copy of Playboy, you are in the pornography perpetuation business, and your misery becomes political.
The truth is that pornography is just a sad affair all around. It is there because men in their hundreds of millions want it to be there. Killing pornography is like killing the messenger. The extent to which Larkin was "dependent" on pornography should be a measure our pity, or even our sympathy. But Motion hears the beep of his political pager, and he stands to attention.

Political Correctness: Robert Bly and Philip Larkin (1997)