It may be a matter of the setting -our GFI is set at 5mA, while the AFCI is set at 30mA- or a difference in the specific electronics of the RCD.
It's a good subject for discussion, though. At least one manufacturer of high-end built-in refrigerators for the residential market (Dacor) specifically states in its' instructions that the refrigerator needs to be on its' own NON-GFI protected circuit.
Where the problem might arise is when the refrigerator is plugged into one of the counter-top 'small appliance' circuits, which are GFI protected.
A few years back, our GFI's were re-designed; the changes are claimed to reduce nuisance tripping.
Personally, I have only encountered the problem with refrigerators that were at the end of their lives - in other words, the GFI's were working as they were supposed to!
Some of the opposition seems to be based upon a 'cost/benefit analysis." That is, the cost of losing a fridge full of food, as contrasted to the small chance of a fault.
