>>96504663
You can be very well-trained but be trained wrong. For example, the Death Korp of Krieg are some of the scariest WW1 style soldiers you'll ever meet.

But they're trained for fucking WW1 style warfare. This, naturally, is not a good matchup for facing the Tau.

>>96496065
I'm sure for them it is. But let's be honest...

The most the Imperium has ever thought about the Tau was that one time Guilliman said their name off-hand during a conversation about how many enemies the Imperium has. And even then I wouldn't be surprised if the guy who mentioned the Tau to Guilliman was fired on the spot for wasting his time.