It's all very simple. We can't fight Islam in the West without fighting the enablers of Islam in the West, namely the Leftists.
And, since the Left has many different and separate aspects, we have to fight against each one of them. Secularism, environmentalism, global warming alarmism, homosexualism, militant feminism, sexual relativism, multiculturalism, anti-Christianity, Islamophilia, post-nationalism, and internationalism are just as important targets to attack as Marxist economics, the expropriation of the capitalist class (or, in its modern reincarnation, redistribution of wealth), and the dictatorship of the proletariat.
Neglecting any of these fronts is like fighting a war leaving a battleground to the enemy, like fighting on the western front and leaving totally undefended the eastern one.