I bought the exact same multi tool probably 9 years ago and was in the same boat with the finish and having to wipe it down. Even posted pictures here to ask if it was normal and was told by most it needed to be returned and the finish was unacceptable. Well a friend had ordered it for me at his cost and I didn’t want to have him deal with it.

Aside from the 2 years it spent in the pocket of packed up snow pants (I thought it lost in the woods) I use it about everyday. My wire cutters are jacked up from cutting steel cable but that was all on me.

All in all mines been great.

That is basically what I be expect of a black oxide finish. Just a thin layer of black colored rust, no?

I think these companies just take the chance that their QC will be good enough. I bought a $1500 playset for my kids. The main swing area was welded at the incorrect angles. They sent me a new one. They also sent me a new slide that was damaged in transit. I still wonder how that could be cheaper than checking the angles in the facility. Or for that matter, shipping the slide with some kind of covering...literally had plastic wrap.

Even if the finish were decent, I couldm't dea; with a black multi tool. Spent too much time in poorly lit comm rooms and other areas, dark tools got lost.
I only have one SOG multi, it's a specialty one with all telecom stuff on it.

I USED to like SOG, but I had bought a Gov-Tac SOG fixed blade fighter style knife and it snapped in half while my friend's young son tossed it around sticking it into the ground. Looking at the broken blade it was obviously of cast type construction. The knife was advertised as a survival type fighting knife, but turned out to be a piece of crappy cast something metal. The price of the knife never suggested it was cast, and it didn't look like it at all. SOG is not my kind of company.

I have the Victorinox SS model, not black - as mentioned it is top of the line.

Also have a Gerber black oxide with carbide insert cutters. Never any black coming off that as I recall. Also very good tool. If you have/get the carbide inserts, DONT twist or wiggle tool as you are cutting, the inserts will break. Steady hold on wire, steady squeeze and it works great. Inserts are replaceable.

Black oxide coatings are a controlled corrosion of the metal surfaces, most often in a rotating barrel submerged in a chemical bath. The process requires washing of parts, oxidizing, and rinsing. Then, the parts are often brought out to an assembly area in bulk, where they slide around in various containers.

Black oxide coatings that are NOT well controlled through periodic chemistry checks and good processes can be as you found. So, 'they all are like that' is likely a true statement. It reflects upon the quality systems and mindset of the plating department. Many black oxide coatings are perfectly serviceable.