I think the problem is the rule itself. A rule of thumb is fundamentally broken if it does more harm than good. The heuristics to drive a decision need to lead the developer to a good outcome if they apply it without overthinking things or have meetings, because that's what rules of thumb are for.

Time and again developers tie codebases into contrived knots by mindlessly repeating the mantra "duplicate code is bad code" because they fail to realize that code that looks the same is not the same code at all, and sometimes should not be the same code at all for a number of reasons. Developers need to think hard about whether a refactorization helps simplify a project, and shoving code sections into multiple unrelated code paths is surely a way to do the exact opposite. Moreso when a mastermind developer opts to add conditionals to force similar code blocks to fit other code paths.