I think he meant that OKW has worse team weapons than OST. He'd have to be pretty delusional to think that the Maxim is better than the MG34.
I tried a 120 in a match today that was infantry heavy on Elst. It got no kills in around 30 minutes of playing. It costs about 40% more than a standard mortar, while having a much slower fire rate and the same damage, just over a little bit larger area. It's the worst mortar in the game.
That is misleading, all mortar have the same damage and 120mm has a larger AOE, the AOE is not "little bit larger". It x150%.
Use the 120 mm vs static targets like OKW trucks and you will see how good it is.