Why is distilled water used for cleaning circuit boards
No, deionized water does not "strip" corrosion.

Ordinary water contains ions that are the result of dissociating various salt compounds. If you were to wash a board with this water, some of those salts would be left behind as residue as the water evaporates. Over time, these salts will react with atmospheric humidity and cause corrosion in metal surfaces.

Therefore, boards are rinsed with deionized water to prevent such residues and the resulting long-term reliability problems.