This article appears to have nothing to do with micro-op fusion, which is an internal optimization in some CPUs. See, for example, section 8.4 in Anger Fog manual [1]. This article is instead about whether a particular operation is better written as a single-instruction memory RMW or as there separate instructions to read, modify, and write.
[1] http://www.agner.org/optimize/microarchitecture.pdf