Most still do so long as the line being drawn is "is there any hypothetical situation in which a 17 year old can legally marry?" Most of those specifically allow older teens (16 or 17 depending on the state) to marry under narrow circumstances, usually requiring any minor have parental consent and/or court approval before allowing it. All states allowed under-18 marriage in some conditions until 2018, and only about a dozen have set a hard 18 limit with no exceptions since then.

With CA being one of the worst offenders in that it has no hard legal minimum age of marriage at all and relies on parents and courts to prevent serious abuse (no minimum but requires approval from one parent or guardian and the court). MA was very similar with no hard minimum at all until recently passing a hard 18 minimum.

Which means if you have the right people in your pocket (a parent or guardian and a judge) you could hypothetically marry someone very underage in CA then cart them off to a state where marriage is an explicit exception to age of consent (such as NM) and engage in legal CSA.