I've since read TFA, as well as many other articles, official correspondence, and case law around the issue. I understand that without the additional ingredients of SNAC/sodium caprate/sodium caprylate, the bioavailability is probably too low to have a clinical effect at oral doses <15mg/day.
I read the actual FDA referral to the DOJ. They don't mention anything about any of what this article touches on. It's not clear that the referral makes correct claims about anything illegal going on. In statements, the FDA says that compounding pharmacies "cannot state compounded drugs use the same active ingredient as the FDA-approved drugs". That's a very brand-new interpretation of rules, and might not stand up to judicial scrutiny. In the context of "shouldn't investors have known that Hims business model is illegal??" -- it makes sense that investors couldn't have known ahead of time that the FDA would claim this.