So was there a specific reason that melee only/ ranged only is frowned upon?

Somebody told me that the reason they don't make a bunch of these lethality items is because they don't want to hinder build paths or whatever . But are specifically targeted to a group, obviously you cant be garen autoing 3 people at once that ould just be silly. But if a huge problem with lethality and whatnot lies in the ranged abusing (kind of like how was overly used on mages and therefore nerfed ) then why don't we make it so it is ranged only/melee only?