That's actually crazy to me. Like, a sealed, generic brand bag from the cold section of a chain grocery store vs a block purchased from the deli and shredded by hand? The difference is massive! Taste will vary between the two anyways but the texture difference is categorical. The pre shredded has grainy flour like stuff all over it, the manually shredded is completely smooth with no graininess at all. I can 1000% tell the difference in any kind of test you want to do.
Where are you buying cheese that this comparison isn't noticable?
Like...in what way? If I buy a block of Aldi's cheddar and Aldi's pre-shredded cheese it tastes the same once it's mixed into something - except the block saves me like 20p and wastes 10 minutes of my life on grating and cleaning up afterwards.
most of my pre-shreded cheese has no such grainy flour like stuff all over it... Harris Teeter, but Kroger before that... I think I can remember once getting a bag with some noticeable anti-caking agent... in my life.
Where are you buying cheese that this comparison isn't noticable?