It solved an immediate problem for them-- the fact that it would go the same way isn't the biggest deal since it doesn't cost anything for the developers just switch to another one.  It probably would have been superior to implement a better approach, but I guess they thought it was better to address it immediately than immediately take the extra time for a more generalized solution.

When tn3 was created it was proposed by some to just reset the chain accepted by the software every major version.   I think discussion on that just landed on that the project could switch to doing that later if problems continued.  For a decade the problems didn't continue. Now that they are back I suspect the project will end up doing something like that.

It's a test harness, the only purpose exists for is the developers testing.  It's often the case that test harnesses have intentional defects to facilitate testing.   It seems to have worked out fine so far.