Conveniently the video proof of them being cracked by bolt cutters is missing.

I've put a hairline crack in a 12mm pewag security chain with 49" Krenn bolt cutters. It utterly destroyed the cutting blades in the process. I'd have needed two sets of blades at least to break one chain. The hydraulic cutters suffer the same problem as the manual ones, i.e. the cutting blades shatter or dull before the chain is completely cut.