Scaling scales both directions
When resizing an object or support enforcer the models scales in the direction chosen and the opposite direction as well, While when scaling a model this isnt a big deal, but when try to place a support enforcer or blocker, its an issue trying to get it both the right size and placment when trying to move just the right side a little further, the left side does as well. Or try to move the top up, the bottom goes lower too.
RE: Scaling scales both directions
Was there a question in there somewhere ? Yes scaling is proportional and happens on both/multiple sides of a modifier. That's the way its been implemented.
If you are unhappy with how it works then may I suggest you raise a feature request at https://github.com/prusa3d/PrusaSlicer/issues where it can be added to the 1235 other open issues. I'm sure the devs will give it the attention it deserves.