ice crash help

why "Multistrike support" doesn't work with ice crash ... it supposed to be work with melee and ice crash is "Attack, Aoe, cold, MELEE" ?!

Because Ice Crash specifically and intentionally cannot be supported by Multistrike.

Ice Crash was the first melee skill the devs introduced to try and defuse the Attack Speed Meta, meant to be rewarding for bigger, slower attacks. It didn't quite work, but it did lead to the creation of Earthquake, which did defuse the Attack Speed Meta to some extent. For Earthquake builds, at least.