You and the guy in the video are total morons, inable to understand a mathematical curve with a limit value. Not 100% sure if there is a limit if approaching infinite, cause I didn't look at the exact formula, but the curves for rares, sets and uniques sure look like they have one. Doesn't matter in practical terms anyways, since MF on a character is limited.
So 1800 MF will only increase your effective MF for uniques by about 60% compared to 300 MF. So that diablo drop is totally possible and to be honest a quite average drop.