The book defines a universal as a concept in which participation is possible: it can apply truly to many things.
This means that the same meaning can correctly be predicated of distinct individuals. Calling one person 'human' does not prevent another person being called 'human' in the same sense.
Hence 'human' is universal. It is not that the individuals share a personal name, but that the general meaning applies to each.
Opening interactive controls...
The source definition of a universal
Universal and Particular — Definitions and Practical Classification
The book defines a universal as a concept in which participation is possible: it can apply truly to many things.
This means that the same meaning can correctly be predicated of distinct individuals. Calling one person 'human' does not prevent another person being called 'human' in the same sense.
Hence 'human' is universal. It is not that the individuals share a personal name, but that the general meaning applies to each.