I wish there was a halfway decent documentary that took a more balanced approach, because if your goal is "better animal welfare" rather than "the abolition of meat eating on moral grounds" then there's actually a lot to criticize and improve on. e.g. I thought "Food Inc" was a lot more even-handed, even though it still fell into some of the usual traps.
I’d argue that industrialized slaughter is just never going to look good regardless of what facility it is. Lab grown meat is something I would support but as it stands today the meat industry is an abject horror and deserves to be exposed.
An example: there's this classic image you see all the time of the cow strung up by its hindquarters, kicking and flailing as it's moved along the assembly line. The problem is that this narrative is literally fraudulent. That cow is already dead, its brain has been destroyed by a bolt gun, and the reason it's "kicking" is because its 100% dead carcass is being shocked with electricity to induce rigor mortis. It's actually illegal to slaughter a cow any other way in a slaughterhouse.
For me at least the reason I hunt is because I love the personal connection I get to what I eat. Being responsible for my food is incredibly satisfying. Lab grown meat to me seems like the opposite of that.