Not sure where you heard that information. I was in Malaysia about two years ago, any significant Malaysian bank will accept your ATM card. And I had no problems while in Kuantan OR Kuala Lumpur. Now, there are banks non-Muslims are not permitted in, but there was only one of those I saw while in Kuala Lumpur.
A bigger issue, at least when I was there and perhaps where your rumor stems from, apparently it's fairly common for people to put a device on the card reader of a legitimate ATM. So, when you stick your card in, it gets your information and can cause transactions to not complete. I was told to do a visual inspection before using any ATM and to physically see if there was anything loose on the card slot. The device is allegedly very discreet.
Personally, I would try to go to actual banks and use their ATMs as much as possible. Still check the slot of course.
So, unless something has changed significantly, your ATM card should be fine.