This is hardly different from being level-synched when you do a normal Haukke run. Since 50 is the required level for those dungeons, they can't weaken you by synching your actual level, but a fresh 50 is vastly inferior to a fully geared one, and to combat this discrepancy and keep the old level 50 dungeons from becoming easier to complete than even Sastasha, a cap on ilvl is the only solution. Ilvl gets scaled down alongside your normal level in lowie dungeons anyway, why complain about it now?