Actually that isnt fully true.
While fight scenes are more complicated a conversation especially ones focused on the face are NOT easier to animate.
We humans are VERY good at reading faces eyes and body language.
So having the complex interactions come across well and not wooden
Is not as easy as people think it is.
It actually takes a lot of work.
Detail shots like close in are ALWAYS more difficult to make it come across well. More distant like in the case of fighting are easier because you dont need the details to be perfect because the audience wont see them as well.