The issue here is mostly ignorance. Wolf tends not to be the hottest of loads, and when mixed with lower grade guns, you can run into issues. I’ve had more stuck cases with brass than steel. Rob_s wrote an article (I think) about shooting steel cases. Just pay more attention to lube.
Scratches the inside of the ejection port? So what? If you use your weapon it will get dings, marks, wear in spots. Worn areas due to high round counts is awesome. Shows that you actually use your weapon.
The steal cases, and their coatings do not leave residue in your weapon. The old lousy neck sealants would, and add that you can get more carbon blow back around the steel case. They might dirty your weapon a bit faster, but more lube will take care of most of those issues. The neck sealant in the chamber can be cleaned out pretty fast with any solvent.
Other reasons, ignorance, fear, uncertainty, lack of an adventurous spirit. Tiny, uh, nevermind.
My 11.5" BCM gun has fired about 4,600 rounds of steel case Hornady practice ammo, and 200 rounds of 62 gr wolf. Aside from a dead primer in a Hornady load, no issues to report. It has gone close to 3,000rds without cleaning.
Some might worry about it wearing out their extractor quickly. Some AR makers use crappy extractors. Put two and two together, and you’ll see that the issue probably isn’t the ammo.
Overall, I’ve fired about 15,000 rounds of steel cased ammo in the last few years (Hornady practice, Wolf, Brown Bear). I’ve had one stuck case. If I can save 1/4th the cost, and get more trigger time, the advantage is mine.