Cheese alternatives exist that are acceptable to vegans.
There is a Dairy Free Cheese Flavour Sauce costing just over £10 per kilo. This product is more expensive than many cheeses and the protein content is far lower than that of milk or cheese.  It will likely appeal to the small number of people with medical reasons to avoid or restrict milk, to vegans with ethical reasons to avoid milk and lastly to very small numbers of contributors to recipe websites who feel they need experience with vegan products. It tastes reasonable and you don't have to use a great deal at a time. Still for most people cheese is better value for money.