Why can't there be a step tangent?

I have some very complex legacy animation clips, but they were meant to be played frame by frame, no smoothing. The unity animation Interpolation made them very weird.

I've been trying ages to find a solution, and the closest thing I found was to select everything and set Both Tangent to Constraints, but that requires all the Rotation be set Interpolation to Euler Angles, which is difficult because there are hundreds of them and the Animation View can't sort them by type, meaning I have to pick the rotations one by one among hundreds of Position and Scale properties. And this clip is not the only one. I need an easier solution.

Please help if any of you have a way to fix this.

 

Unless they changed something in the latest build, there IS a step tangent choice.

 

Yeah, I am aware of constraints tangent, but in order to convert the existing animation clip to use constraints tangent, all the rotations' Interpolation must be set to Euler Angles.
There are hundreds, and I can't manully select them one by one. At least the animation view should have sort by type option so that I can select all rotations easily