The methods you point out are different way to change the same property, which is fine. VTK has a lot of redundant API as you say so and it is practical.
The problem with the threshold API is that it changed multiple properties with a single call.
If adding these methods make the API better to use, then why not add a ThresholdByUpperWithComponentUseAll, a ThresholdByUpperWithComponentUseAny and a ThresholdByUpperWithComponentUseSelected ? This is the same idea just applied to other properties.
But we clearly do not want that.
As for adding them back, it’s too late imo. The methods have been deprecated and removed.