"give 'em hell, Harry!" at Harry Truman's rally, he replied that he didn't have to give them hell, he only had to tell the truth and they'd THINK it was hell. As for the video in question, which i haven't watched yet, references to slavery in the way we treat animals is one of those uncomfortable truths. When you hold an animal captive and confiscate it's eggs or milk or offspring, and then take it's life that's pretty much slavery and pretty shocking when you think about it.
I get a kick out of the point about leather shoes. The implication is that if you haven't yet gotten every bit of unnecessary animal suffering out of your life, then your quest has been for nothing. the fact is that these things are done in stages as people realize they can do just fine without causing needless animal suffering now that our big brains have figured out substitutes for everything we think we need. As for b-12, yes it's best for vegans to supplement to make sure they are getting enough. Getting enough b-12 through plants is an ability we have lost over years of eating carrion and mammalian bodily fluids so consistently.
Imagine if you had no issues at all with the way animals were treated in factory farms at all, and you just wanted to show pictures of the operation, just as you can watch interesting videos of peanut butter being made. We've all seen them, the jars moving swiftly done the line then each being filled with the exact same amount as the one before it, another arm slapping a label on the jar, etc. the point being that if you show pictures of how your "meat" is "produced" , even if you love factory farming and and meat, the videos would be shocking just because it is such an awful, evil, vile violent act.