Could you add a reference or link to more information about this statement, would be great!

Not sure why you ask for a reference. Is that because you think this is not right or you want some more logic behind it? Double slit experience and many experiments can demonstrate QM in human scale. So my point is if we do not go small, we are seeing the average behavior of the quantum system and the environment. That creates a constraint that we need equipment to isolate the environment well.