If you get to 140 in 4 hours we all agree you can inject all you wish with basically any safe marinade you wish.
Not sure what you mean by over responsibility? If you say that Purists shouldn't comment or clarify when potentially unsafe information is put on the forum then I respectfully disagree?
I would need to get a second opinion but "almost freezing" a marinade slows the growth of bacteria in the marinade but within a short period of time after injecting the marinade is at the meat's temperate and bacterial activity gets a kick start. I know freezing is effective for Tric but to have any affect on bacteria and spores you need to freeze for long periods of time.
I inject chicken and small turkeys regularly before smoking. I boil the injection, then run temps high enough to get the bird out of the danger zone as fast as possible. I usually do not inject pork butt or brisket. No need to, I like the flavor and moisture of the meat without injecting.
When I do large turkeys I will not inject until after the bird has been on the smoke for a while. I will make a marinade of butter, garlic, soy sauce, salt, bring to a boil and inject to help moisten the breasts of the bird
Maybe you can point out how I am "breaking the rules"? If I am please show me where I am making my mistake and I will correct my procedures.
Not sure how the "Bacon calculator" comes into a conversation about injecting. A lot of the credit for the bacon calculator goes to the comments I received from other members of the forum that reviewed and edited it.