"I was told that the hot dishwasher moisture will soften the adhesive, destroy the laminate and the kitchen cabinet. "

It will.

"was told that it is not necessary to have a moisture barrier/deflector with marble counter tops. "

It's not.

"Aren't all counter tops needing the moisture deflector to prevent moisture on the cabinets? "

No, it's there to protect the underside of the countertop. It does nothing for the cabinets themselves.

xedos, we see pictures of full-size-panel dishwashers all the time. Are they all "rolling the dice", or is it only laminates that are a problem?

I read the install directions before my Miele was put in and it said, from what I recall, that it was only needed for wood or laminate type counter tops to prevent the moisture from penetrating those materials. Stone and other hard surface materials won't absorb that moisture and don't have the same issues as laminates and wood from what I have read.

Phil

Based on phil's post, i realize I should clarify that I was curious if its a problem with a laminate cabinet panel on the front, not laminate counters (our counters are quartz).

My miele is paneled, not laminate, but still paneled. I have not had any issues in the 1 year we have had it so far.

Phil

All my washers in the last three homes had the moisture barrier. The counters were granite, corian and hickory wood. I could not recall if this strip was for the counter or for the cabinets.
I have soapstone presently with a moisture barrier so I assumed you need it for all counters. I searched the Internet but only found posts saying you need the barrier for laminate counters. Miele installation instructions on their web page said you only need the barrier for laminate countertops.

Thanks for clarifying .
It sure helps to confirm info

Hate to break it to you all but your cabinets are most likely made of very similar materials to a laminate counter. Cabinet cases are made of plywood which is laminated layers of wood. The cabinetry will take abuse from the steam created by the venting dishwasher. While not directly above the dishwasher like the counter top, the steam will hit the top and be deflected towards the sides. Inevitably the wear will show and need repair. That is not a defect, it's just a fact.