You're still underplaying just how radical this DIY approach is.
Imagine you decide you are a modern day Robinhood, and you go around the U.S. breaking into medical facilities and stealing Epipens to distribute them for free to the general populace. You do this until you and your band get caught, and which point you go to prison.
At the end of your run every person who received a free Epipen got the same quality device as the people who paid exorbitant price for an Epipen. To the degree that you inspire others to do this, they are bound by the same risk of prison time. Finally, since the price you charged was $0 there is no financial incentive for copycats to distribute fake Epipens (or at least if somebody does they must be a bad actor with ill intentions, or they must charge a fee in which case potential buyers will rightly be skeptical of the product).
What the DIY chemist apparently wants to do is persuade non-experts that they can produce Artisanal Epipens that are ostensibly as safe as the real thing (or at least safe enough that the risk is overridden by the alternative). But that is only an argument for a doctor to use an artisanal epipen if it is the only thing that happens to be lying around-- it's not an argument for persuading the general public to practice and spread the idea of DIY non-expert chemistry.
DIY chemistry doesn't come with public policy expertise. It doesn't come with trained (and funded!) epidemiology. And if their DIY ethos goes horribly wrong-- as the "roll-up-our-sleeves-and-research-our-own-vaccines-schedules" movement has-- they won't have the competence in statistics to know just how dangerous their movement has become in terms of public health. Worse, where science tends toward rigor, verifiability, and a narrowly defined scope of research, these DIY chemists will likely be skeptical of the published canon and "wing it" by trying to do their own epidemiology (because after, ignorance and lack of training didn't stop them from being a chemist...)
Worst of all, unlike my Robinhood example there is no natural filter to keep otherwise good faith actors from making decisions that will have terrible consequences for themselves and others. To steal Epipens you've got to break in to a physical place and potentially physically harm or threaten a security guard. This filter keeps tens of millions of people who are no doubt convinced of the deep unfairness of pharmaceutical prices from becoming an angry and dangerous mob whose violence quickly outweighs the single benefit of redistributing epipens to the poor.
Based on that, DIY artisanal epipens are more risky and can scale into a public hazard more easily than just robbing a pharmaceutical warehouse. So I claim that casually encouraging people to make DIY epipens without a systematic, well-tested, and well-funded research regimen is more dangerous and irresponsible than just stealing extant epipens.
So if you're the type of person who rejects robbery out of hand, you probably shouldn't entertain the idea of Artisanal Epipens, either.