Terry Eagleton argues for a vague type of Christianity and is also an admirer of Karl Marx. This author doesn't know how Eagleton reconciles his support of Christianity with the traditional Marxist view that religion is the Opium of the people.
Marxism
During the 20th Century there were any number of attempts to establish Marxist economies and all became devastatingly inefficient. Marxist economics can only be imposed in dictatorships where the people can't vote against the Marxism that's forced onto them. Empirical evidence suggests the most likely result of yet another Marxist experiment would be yet another Marxist dictatorship.
Speculation
Christianity and Marxism are both Faith based systems, both defy logical and empirical investigation. Perhaps a few Marxists are tempted to look to religion and try to attract those who follow faith rather than empiricism.
There is a good and a a bad side to Christianity, see the category page