There is no contradiction in what I have said.
You probably failed to notice that I showed the original poster how to arrive at a good rolling ball fillet solution while everyone else is saying that’s not possible in Rhino
I suspect the real source of your negative attitude is that you have no appreciation for the tremendous value of being able to create true rolling ball fillets as transition surfaces. Good rolling ball fillets are extremely robust surfaces. True fillets generally have much better tangent continuity and that’s important if you want to build complex models with overlapping features and overlapping transition surfaces between features. If you try to build complex objects with overlapping transition blends that do not have rock solid continuity you will find it to be a lot more difficult then if you do. So even though Rhino makes the user do an enormous amount of unnecessary work to create true fillets it will pay off in the long run if you are building something very complicated.
Its easy to demonstrate the greatly superior continuity of true fillets.
Open this model: Offset_These_Surfaces.3dm (675.6 KB)
then window select all the surfaces and offset by 2 mm.
Then select the result and join it. Everything joins nicely.
Now try the same thing on the model you posted (123.3dm) . First explode it and then select and offset the individual surfaces by 2 mm,
What you will find is there are lots of places where your model has poor continuity and as a result when you try to join all the offset surfaces there will be many places where the surfaces won’t join.
Part of the problem in your model is there is a bug in offsetSrf and it can’t correctly produce a closed fillet offset in fillet loops that are one surface connected to itself even though the offset result has ends within tolerance they can’t be joined. But most of the edges that won’t join are due to the poor continuity of the fillets in your model