Marker Tag doesn't make hitbox small anymore

Armor Stands with Marker:1 seem to have their full hit box since you can hit them VERY easily with snowballs.

Pretty easy to test, make an armor stand with nbt Marker:1 then throw snowballs at it, pretty easy to hit it.

Unless I am confused how Marker 1 is suppose to work it should be hidden and not interfere with stuff right?