Because it is unnatural. Moving in zero gravity means you have to be deliberate and careful in how you move since you're used to having resistance (ie your feet on the ground) rooting your body. Moving one body part moves others you aren't used to because of that.
A lot of the "naturalness" of normal motion is due to the pendulum-like motion of our body parts in a gravity field. Experience has taught you to expect that. Absent that, the motion looks unnatural.
Raving_Lunatic69 t1_iuj4lun wrote
Because it is unnatural. Moving in zero gravity means you have to be deliberate and careful in how you move since you're used to having resistance (ie your feet on the ground) rooting your body. Moving one body part moves others you aren't used to because of that.