Why did some scholars criticize overly rigid applications of the Lachmannian method?

Scholars have criticized the rigid application of the Lachmannian method (or stemmatic method) primarily because it was often applied to texts for which it was unsuitable, leading to "grotesque" results.1

Key criticisms include:

• Methodological Misuse: Critics argued that the method was frequently used to justify a "best manuscript" (codex optimus) on "scientific" grounds, even when common sense indicated the readings were not authentic.1
• Logical Circularity: H. Quentin noted that the method relies on identifying errors to build a stemma, yet the identification of those errors often presupposes the very stemma the editor is trying to construct.1
• Incompatibility with Medieval Texts: Unlike classical texts, which often passed through historical "bottlenecks" that simplified the evidence, many medieval texts exist in multiple, equally valid redactions that cannot be reduced to a single stemma. Furthermore, the lack of strict linguistic and stylistic canons in medieval works makes it difficult to reliably distinguish between variants and errors.1
• Diversity of Transmission: Scholars like H. Sauppe emphasized that transmissional situations are too diverse for a one-size-fits-all approach, and in some cases, classifying manuscripts is impossible.1

Ultimately, modern critics advocate for a "cautious empiricism," rejecting any method that conflicts with common sense and emphasizing that texts should be judged on their intrinsic merits.1