Soil vs Sand Greens

Why are the white greens different from the red and blue greens?  Why do they feel softer? The white greens were built 100 years ago and were what we call "push up" greens.   Native soil was just moved and shaped to a design and grass was planted on top.   There was no drainage installed and the native soil (clay) has a tendency to hold moisture following a rainfall.   When the white nine was  renovated in the late 90s, there was no drainage installed in the greens and they kept the same soil rootzone.  Only the grass species was changed.

Conversely, USGA sand based greens are designed for drainage and dryness and firmness.   Sand drains better than soil and the red and blue greens also have a drainage system built into the subsurface.   The combination of a sand rootzone and subsurface drainage provide for a firmer and drier putting surface.