I don't have references for 2000 article to hand, however in my opinion it's not historically important. The transport strike is flagged up by KPD detractors, from both left and right as part of wider attack on physical force anti-fascism in general.
Here the grandly proclaim is the photographic evidence of widespread and routine collusion between the the Stalinists and the Nazis. The underlying liberal message being that at the end of the day, there is will always be a hidden symmetry, between the violent extremes, with one side being hardly any better, or more moral than the other.
But of course the fact that this singular incident has gained such notoriety is proof in itself that there was no such collusion.