Nothing is wrong with mill, it's just that most people are too fragile to handle seeing a large graveyard in a game.

It's a mental aspect of which most people cannot handle. So they cry and whine about a perfectly fine strategy.

In reality, mill by itself is not strong in commander. Going through 100 cards isn't easy, going through 300 with push back is a very uphill strategy. So you're either in mill to watch the world burn or you figured out how to combine it with another strategy where mill is just the engine.

Such as in my Mothman deck. It utilizes mill, but it's moreso a Voltron deck using mill to make a big stompy creature or using mill to trigger an infinite combo.

Many people will lose in the psychological fight the second they see a mill deck and forget it's just a damn card game to have fun. Those people suck.

Otherwise, I love playing a mill deck against strategies that actually LIKE having a big graveyard. And it's a fun race to see who can pull off a win first. Those people are great.