It’s a broken system, no argument there. The dedicated drops could definitely use a buff, but farming should still be farming. It just shouldn’t require 3 days of farming to get what you want. A few hours for a really close to perfect M4 only drop would not be unreasonable. You would get several of the dedicated drops in that time, but getting the one that’s about as close to perfect as you could ask for would still require some significant dedication.
The paragraph right after the one you quoted already directly answered this concern. I’ll absolutely agree that there’s no point in farming until you’ve hit level 50 and have Mayhem unlocked. That said, M2 appears to be the best balance between the time it takes to complete the run, and your odds of getting the item anointed. Yes, the odds of being anointed is lower, but you can make 4 to 5 times as many runs on M2 as you can in M4 in the same amount of time. Since your odds of getting the dedicated drop at all are the same at both levels, it’s better to take 4-5 times more drops with a 50% lower chance of getting it anointed if you get the dedicated one.
And that’s assuming you don’t die in either one. I’ll bet you die much more often in M4 requiring a restart without the loot.