You and everyone in the food science field can convince me to stop this by providing a peer reviewed article indicating that roasting garlic does not get an internal temp hot enough to kill botulism (I will actually check this next time) and that botulism spores can inhabit the interior of the garlic. I would expect the latter to be false even if the former is true (the surface is the place all of these things grow). I also suspect that the former may be true - you roast garlic enclosed in foil and covered in oil, which are correct conditions for raising the internal temp past the boiling point of water without the water being able to completely boil off, and the sugars in the garlic do caramelize, indicating a relatively high internal temp (Fructose starts caramelizing at 110C).
You are asking me to follow the words of scientists who have not done the science. I am asking them to do the science. Particularly since their mechanistic theory has a huge hole: the actual processing of the vegetable. By the same standard, they should be telling you that cooked chicken and eggs are both unsafe - the raw product carries salmonella and the final cooked form is an ideal environment in which salmonella can grow.
You know as well as I do that scientists do not publish negative results. I haven't found anyone replicating growth of botulism in raw garlic, though, so I assume that the studies just haven't been done, not that anyone is hiding anything (this would be an interesting negative result). There have also been 0 food safety incidents, as far as I can tell, implicating cooked garlic stored in oil - it's all raw garlic.
With regards to this publication, I am mostly shocked that they are recommending acidification with no expiration date - they should be giving it a very hard timeframe of months if they want to hold themselves to a consistent standard.
It costs the FDA and USDA (and these people at UC Davis) nothing to say "conditions seem fine to grow bacteria so don't do it" without checking whether the process is actually safe with acceptable food handling procedures. I am fine with the FDA saying that - I have no plans to sell food - but the FDA has a lot of rules that are written out of an abundance of caution rather than out of need.
By the way - another way of making roasted garlic in oil is to "confit" the garlic completely in oil - submerge the garlic in the oil and cook it at 275F (~135C) for ~3 hours. This will absolutely, without a shadow of a doubt, raise the internal temp of the garlic to 135C, and if you handle it correctly, you will not re-introduce any bad bacteria. The FDA still won't let you sell it and that still goes against the UC Davis recommendations, despite being obviously sanitized. It is also delicious.
In other words, science is smart, but scientists can be dumb. Follow the science, not the scientists.