Certain items in the holodeck are clearly replicated instead of holo-projected, such as food and drink.
So it must be the same with clothing. In 1979, TMP showed that even in the 23rd century, it was possible to materialize synthesized clothing directly onto a body.
Since people of the future seem to have retained our primitive cultural notions of modesty for the most part, it would be embarrassing if you had to leave the holodeck in an emergency situation but then have your clothes vanish the instant you exited.
Kor