Anyone above who has cited ankle support should be entirely disregarded. They have no idea what they're talking about. Your ankles are effectively entirely immobilized laterally with both styles.
If you have seen such a thing, that is a function of improperly sized and/or laced skates. It is absolutely not inherent in the design. I can only assume whoever put them on didn't know what they were doing.
edit: unless you mean rotation. In that case, again, no different between hockey and figure skates there. You have to be able to rotate your ankles to function.
Ferzerp is very much correct. It's common to see people in rental skates at the ice rink with their skates splayed out at 45 degree angles. This is more common with figure skates than it is hockey skates, but it has nothing to do with ankle support in either skate being deficient. In my experience (been skating since I was a very young kid, mother was a professional figure skater/coach, played hockey for ~20 years, have owned dozens of pairs of skates), figure skates are a bit more sensitive to fit than hockey skates, but fit is important for both. Go to the ice rink and watch an open practice session or some lessons / team practice with figure skaters / hockey players. You generally will see no-one with their skates splayed out because everyone has equipment that fits. Both sports are very expensive compared to the other things your kids can play / do. When you are paying thousands of dollars for ice time a year, you make sure your gear works (you also know how to lace your skates).
Note that I'm not saying that either type of skate is superior. Hockey skates are more rigid and have more padding because the sport involves fairly dense objects being shot at high velocities. Figure skates do allow for a bit more freedom of movement because the footwork a figure skater has to perform is much more intricate. When laced and sized properly, both should feel like an extension of your body more than an article of clothing.
I should also note that MOST rental skates that I've seen are broken down well past the stage where anyone serious would have thrown them away. If you are a casual skater a pair of good skates will last you for years. If you are on the ice 5 days a week, you can go through multiple pairs of skates in a year.