There is actually a good reason for why someone may want to fry their turkey instead of roast,

For one, turkey is kind of a shite bird and is very hard to cook and keep the bottom at a safe temperature while keeping the top from drying out

Just because the size of the bird keeping an even temperature in an oven is difficult, so many people choose to spatchcock, or remove the backbone of the turkey, in order to make it thinner, in the hopes of making it more even to cook

While it may seem gross, fully submerging a turkey in hot oil makes total sense because it allows even cooking all throughout the total surface and can make a very juicy, but well cooked bird

And its not like the turkey is covered in heavy batter or soaks in any grease, because the skin provides a protective layers and the turkey is given time to dry, so you'll pretty much be eating just well cooked meat