Ang Moh is a colloquial term used locally to refer to Caucasians. A large section of society uses the term and most of the time it is used without racist or malicious intent.
It would be racist if an individual uses "Ang Moh" in conjunction with a descriptive word affixed at the front. For example, "Chao Ang Moh" which literally means Smelly Ang Moh, or "Ka Ni Na Ang Moh" (translated" f*** your mother Ang Moh). These would be termed racist.
As the saying goes, when in Rome, do as the Romans do. The term Ang Moh is simply the local way of addressing an individual of Caucasian ethnicity and is not meant to be interpreted with a racist lens. And Ang Moh is a term our uneducated forefathers used to call their colonial masters.