Why does the Left in the West make common ground with Islamists who violently reject all of the Left's positions?

This article provides an excellent discussion of why leftists support Islamists. Leftists generally support equal rights for women and gays, free speech, tolerance and oppose religious extremism. Islamists hold opposite views on all of these issues. One would think that leftists would be leading the opposition to Islamists.

In reality, leftists act as apologists for terrorism and the Islamists. The article states that

Glazov concludes that the Left’s “romance with Islamism is just a logical
continuation of the long leftist tradition of worshipping America’s foes. . . .
The Left clearly continues to be inspired by its undying Marxist conviction that
capitalism is evil and that forces of revolution are rising to overthrow it —
and must be supported.” On that basis, militant Islamism is regarded as a
“valiant form of ‘resistance’ against American imperialism and
oppression.”

Hatred of capitalism and the USA trumps all of the other shibboleths of the left to justify making common ground with Islamists. This is the case even though the first action of Islamists if they ever won power would be to behead leftist leaders.