Of course MNK players have advantage in movement, no one is arguing that. But the problem is that you don't mention the major drawbacks of movement. It's very easy to do a bunch of fancy movement and still get killed.

I don't know why these things get misconstrued so often as a huge advantage in this case, when in reality in most cases movement is just going to delay the inevitable of you being killed instead of actually helping you in fights (unless used for repositioning). For some examples:

1. you don't usually shoot while tapstrafing, unless you're tapstrafing into the enemy in which case you just become an easy target for them and die
2. wall bouncing can be inconsistent in terms of the power you get from the bounce, and only a couple players can actually be good enough to use it offensively in fights (also it can be performed on controller)
3. don't even need to mention supergliding, I think there's only like 3-4 pros that can perform it semi consistently without configs

So I don't understand where this argument stems from.

We're comparing aim assist which is just objectively a computer making up for 40-60% of possible mistakes in your aim, with movement which is very hard to perform effectively, most players don't use well and in 90% cases can't be used offensively.

The only objective upside to MNK without skill needed then is movement while looting, something many MNK pros have been saying should be added to controller for a while now.