because these traditions fail when being tested by scripture.
>>Correction. They fail when being tested by private interpretations of scripture.
They fail under the plain sense of scripture, under any translation. They're only deemed acceptable due to extra-Biblical reinterpretations and decrees of fallible men who have the presumption to deem themselves infallible.
Scripture needs no interpretation, its language is simple, and intended for all.
Ever notice how Christ carefully explained each parable to his sheep?
Interpretation is always error; plain reading is the word of God. Traditions are a barrier between the sheep and their shepherd.