Matthew 18:20
20 For where two or three gather in my name, there am I with them.
Hey, look there, we don’t need dead humans as mediators according to this source called The Bible. Is that source not good enough for them?
No, it's not.
The work of Jesus on the cross isn't good enough for them either. Since they seem to feel the need to add to even THAT, does it surprise anyone that they feel the need to add to Scripture because it's not sufficient?
If the Living Word isn't good enough, the written word isn't going to be either.
Well...
Jesus answered, The work of God is this: to believe in the one he has sent.