The book restricts the ism of lā acting like laysa to indefinite nouns. Thus لَا زَيْدٌ قَائِمًا is not a valid illustration of this governing pattern.
This does not mean lā can never appear near a proper noun in other constructions. The point is to identify the type of lā and whether it governs.
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Ism of Mā and Lā Resembling Laysa; Khabar of Lā of Generic Negation
The book restricts the ism of lā acting like laysa to indefinite nouns. Thus لَا زَيْدٌ قَائِمًا is not a valid illustration of this governing pattern.
This does not mean lā can never appear near a proper noun in other constructions. The point is to identify the type of lā and whether it governs.