Being left of center is not solely defined by being Marxist, and one country, even if it actually was Marxist and not 3 Capitalisms in a trenchcoat, would not define the standard of what constitutes "left" in the world.
I'm not saying Marxism isn't Left. I'm saying it's not literally the only thing that IS Left.
The metric you are using is not the metric the actual real world uses for center left. You are bringing your internet lefty definitions and declaring that I'm wrong to say only internet lefties would use them. Major parties in the middle of the political spectrum are not typically pushing for the overthrow of Capitalism.