After butchering a carcass, you're left with a lot of fatty trimmings with small amounts of meat attached that are uneconomical to recover by hand. If you gently heat the fat trimmings and spin them in a centrifuge, you cleanly separate the lean meat from the fat. That process weakens the cell walls of the muscle fibres, which increases the risk of bacterial growth; to kill the bacteria, ammonium hydroxide gas is used to raise the pH. The FDA deems ammonium hydroxide to be safe, so it is widely used in US food manufacturing as an acidity regulator and antimicrobial agent. Other regulators disagree on the safety of ammonium hydroxide, in which case citric acid is used.
The production of LFTB is no weirder than any number of other food processes. It's a simple, efficient method for separating meat from fat. The media have made a mountain out of a molehill by sensationally revealing a "shocking secret" that is neither shocking nor secret. Personally, I think that a lot of consumers just prefer not to think about how meat ends up on their plate and recoil at any discussion of the process that turns live animals into hamburger patties.
We really need to be talking about the use of antibiotics as a growth promoter, which is a slow-motion catastrophe that the US regulators are largely ignoring.