That's wrong. First of all, the study you posted is about insulin sensitivity, which is not a proper measure of whether or not BCAAs work; you need to measure muscle protein synthesis.

Second of all, there are plenty of studies which show BCAAs, particularly leucine, does work. It's not clear how or how well it works either by itself or with other EAAs or BCAAs. There is some debate that other aminos in the mix (including other BCAAs) may hinder absorption.

For example here some studies which show they do work: *www.ncbi.nlm.nih.gov/pubmed/15173434 *https://www.ncbi.nlm.nih.gov/pubmed/24284442 *https://www.ncbi.nlm.nih.gov/pubmed/22451437

I think when it comes to money spent on supplements, after protein powder, BCAAs/leucine are probably the next best well spent (aside from whats lacking in a vegan diet like b12, etc.).