There's a world of difference.
MMS tastes like Chlorine bleach to me. It's taste is repulsive and ingesting a lot makes me want to vomit.

Oxalic Acid is a natural component of many foods. Carrots, and chocolate are especially high in OA. Pure OA tastes like lemons. It's tart, and sour. It also tastes like pure vitamin-C.

I don't believe Miracle-Mineral-Supplement is a natural component of any food. The body's selective faculties, which help the body to distinguish healthful from toxic substances, find OA much more pleasing than Miracle-Mineral-Supplement .

MMS:
NaClO2 (sodium chlorite)
must be activated...

OA:
C2H2O4
does not require activation, but does require distance from EMF's once consumed.

Entirely different chemical formula.