While there are many views as to what Christian Socialism is or is not: from Leftism's perspective this is what they see or relate with,
When the different values have been hammered out some groups think Christian values will always pull any and all groups to the right side of their values. A basic reason for this is directly from the phrase: "Render unto Caesar what is his." This is to mean that we must be civil and responsible even to those who are unjust towards us while peacefully working for a better world. Karl Marx in his critical analysis and manifesto referred to this as "opiate of the masses" among other words. If we were to draw another picture like the one above from a rightism, it would look much the same, again Christianity always pulls to the right of most boxes, curvature, or scaling of -ism's.
The failure here is Karl Marx's, to see or understand future variables or endless possibilities. Marx was not the only person to suggest socialism as a transitional backdrop to a perceived future. Most of the works printed by Marx were not published until well after his death by Friedrich Engels who paid a genteel salary to Marx for his time and research. The only reason more people quote or cite Marx is not that he was any better a thinker, he was not, but that he had more books publish. There are plenty of non-Marxist writers and theorists of socialism and most were directly from Christian schools of thought or exposure to Christianity.