"Make-work" carries the connotation that the productivity of the worker is less valuable than his pay. "Less valuable than optimum" is not the same as "less valuable than his pay". Furthermore, "low skills" carries the inapt connotation "very low" (and low-testing doesn't necessarily imply low skills anyway.)

The problem is that someone who is either marginally less productive, or marginally worse at testing, can find his ability to get a job decreased by an amount all out of proportion to how worse he is, if all employers use the same measure. Ensuring that such people can get jobs isn't make-work.