I run steel cased Wolf, almost exclusively, through my M4. Many thousands of rounds. No problems.
It is soft steel, and is no harder on the bolt/extractor than brass in my experience. I've run over 1,000rds in a day through my M4 on a couple of occasions. Have not even needed to replace an extractor yet.
Even the U.S. used plenty of steel cased ammo in WW2.
Don't believe everything you read on the internet.
"Obama has ordered the launching of more Tomahawk cruise missiles than All the other Nobel Peace Prize winners combined."