Will someone please explain to me the massive double standard going on here?

Ok, so Mordekaiser's new E basically does no damage. During the work on the rework CertainlyT said this:

E in my mind is most healthy as a "parry" ability that provides a lot of instant shield. As a nuke, it lacks good play against most opponents, who can't help but get into its range.

Now, this isn't a point and click stun that has an 80% AP ratio ( ) its an ability that only does damage. It is certainly true that if you're in range you'll basically get auto hit with it , but we have an entire class of champions (i.e. Marksmen) who's entire paradigm is point and click undodgable damage if you are in their range.

Will someone please tell me why 700 range AOE crits 1.2 times a second (6 times over 5 seconds) is perfectly health and balanced for the game , while an ability which can only be used once in that time frame (Siphon of Destruction) is unhealthy for the game?

Please understand that I'm not saying Marksmen are overpowered or unfair in how they work; but there is a huge double standard in how undodgable ranged auto attack optimization is treated, and spells which only do damage, but auto-hit. Because Mordekaiser is not the first example of this kind of spell being changed for "game health reasons" ** Edit: I want to be clear here - the Mordekaiser changes are a symptom of a larger problem: Why are targeted or auto-hitting damage only spells bad, while auto hitting attacks with a much higher sustained higher damage output perfectly fine?**