He suggests that low SHBG will free up more estrogen suppressing test. Also more free test also acts on the feedback loop suppressing test from going higher. True that steroids lower SHBG, all steroids do, contrary to what some bodybuilders believe. But steroid users don't have to worry about a feedback loop. There's been lots of talk about how you don't want your SHBG very low, there are many complicated reasons, too long for getbiggers, but for example bound test can have effects and SHBG extends the half life of injected testosterone 
I admit my perspective is narrow and you are probably right.
