I think the point of their comment is to say that the idea of critical support is used more these days by western leftists to distance themselves from people who we shouldn't be afraid to openly support than it is to support them in any real material way.

Ultimately that distance is more useful for maintaining the status quo than it is for actually supporting the people who are on the same side of the primary contradictions as us.

Critical support by a well informed Marxist to a like-minded and open minded audience is not what rad lib celebrities are doing when they publish in the guardian