Mind you, they get the details right on why the Battle of Hoth was such an unmitigated disaster for the Empire, but they miss the ‘why.’ It’s actually very simple: Darth Vader had no intention of ‘winning’ that battle in the first place. His long-term strategic goals absolutely required Luke Skywalker escaping that death-trap (and, subconsciously at least, Leia Organa as well); Vader’s original plan must have been to encourage the Rebel Alliance to make an orderly retreat and evacuation – but one where Vader could easily dedicate resources to securing his kid in the process. Only, Admiral Ozzel’s scream-and-leap messed all of that up, so Vader had to spend the next few days messing up the attack and Force Choking idiots*.
Mind you, Vader was always pretty sh*tty when it came to strategy. As witnessed by, well, most of Episode III.
*Which, admittedly, must have been a temptation for him to do all the time anyway.