With regard to what you are 'supposed' to experience with dairy allergies, I have an observation. I suspect that rather more than a few of the 'allergic' reactions people suffer with are actually just normal responses to foods that they are not meant to eat. For example, some people experience increased mucus production, sinus problems, acne and other skin disorders and stomach pain as a result of milk/dairy food consumption. I would suggest that these are not really allergic reactions so much as they are the body's natural reaction to a food that is actually alien to humans.
In short, I would suggest that there are no redeeming features of yoghurt or other dairy products and as such that it is not a good idea to find ways to ingest them -- such as making yoghurt. (Or, if there are any redeeming features that they are heavily outweighed by the negatives.)