RE: "and are all rooted in our Baptism"

Why not describe what we are rooted in using precisely the terms that God's own Word uses?:
We are "rooted and built up in him" (Col. 2:7a), that is, in Christ himself.

Are all who have been baptized now "rooted ... in him"?
Have all who are now "rooted ... in him" been baptized?

Were those who faithfully followed Christ while he was on earth not "rooted ... in him" well before he instituted his baptism?