Dodging cc skillshots

So I don't play league nearly as much as I watch videos of pros playing league on youtube. The cool thing about them is that they can slow down the game, and zoom way in on important fights. A recurring theme is dodging skill shots and being hit by them anyways. When they go slow motion and zoom way in, you see that a blitz hook for example wasn't even close to hitting. But then blitzes whole arm and fist disappears, and reappears on top of them and boom, they get hooked or snared by something that wasn't even close.

I'm sure the only reasonable explanation is "oh hitboxes blah blah." Sure I can see that. But jesus, the hitboxes are humongous if that's the case. In my own games I'm playing the same thing is happening and since I saw it so much in youtube videos now I'm like "wow...this sucks!" Just yesterday I dodged a hook on vayne with my tumble, and to me it looked like I was far as hell from the hook... Got hit anyways. The youtubers nightmare transfered to me. It's kind of annoying honestly lol. What's the point of dodging if it isn't gonna work?? cmon now!