Ice Type SHOULD NOT resist Water Type attacks. Water melts snow and ice.

>but ice types freeze water....

Yeah, offensively. When using offensive attacks. But if they're not currently using an Ice Type offensive attack, then incoming water attacks are not going to miraculously passively freeze (or would do so rather slowly I guess).

What SHOULD happen is that Water Type should be weak to Ice Type attacks. And along with that, Water Types lose common access to Ice Beam.