I was at some Tufts discussions to incoming students a few years back, and the overlying theme to this FR ear was globullization. Typically, across colleges/univ across the US, a semester of the Junior year has been for travel (with the study programs that really have no counterpart outside the US the exception, where the 4-y student does no semesters abroad).
Perhaps that is not enough globullizing the student, and they prefer to start earlier... pre-Freshman. That way, they don’t waste Freshman/Sophomore before they are properly glowbullized.
American students meet so many foreigners and immigrants in their own colleges, plus ethnic minority groups in college, that a semester abroad is now redundantly wasteful.