I couldn't find much on people using red wine vinegar for dreadlocks, so would it be a good enough substitite?
ACV is the normal choice because you tend to be able to buy it bulk cheaper than other vinegars and it's not quite as strong on your eyes and nose. Other vinegars will do the same cleaning job, but might need diluting down a little. I cannot be 100% certain whether you'll have any other issues with red wine vinegar though, as I haven't used it / seen anyone else use it so I'm not certain whether the strong colouring would cause any problems.