If your scores didn’t test you into geometry, it’s because they’re not confident that your algebra skills are where they need to be. Algebra is the basis for every other math course you’ll take; you’ll want to make sure your skills are where they need to be.
The reason you want to go to this school is because of the education they provide, right? So take them at their word when they say you should retake algebra. If they didn’t know their stuff you wouldn’t be considering going there.