I can’t speak for all vegans, but when I ate a vegan diet, I didn’t care about foods that were potentially in contact with animal products. The point of the lifestyle choice (for me) is to decrease the demand for meat. I might be eating a fraction of a portion of beef when I eat an impossible whopper, but no beef is being bought or sold. So yes, there are plenty of vegans out there who can eat Oreos without a guilty conscience.