As any EE knows from linear elements course A, a linear two-port network is reciprocal. If it is not reciprocal it is not linear.
The simple conclusion is that if it matters how you orient the cable, then it has distorsion.
Directional cables have the shield disconnected at one end to ensure there is no LF current path through the shield, thus minimizing mains hum picked up by high-impedance instruments.
Of course, balanced cables (where the shield is exactly a shield, and not also a signal path) do not have this problem.
The Rane Note on sound interconnection has more info: https://www.ranecommercial.com/legacy/note110.html
You might get the same response in a data center if you say “the color doesn’t matter because the cables are all reciprocal.”
Additionally, labels on datacenter cabling tends to be less cryptic like "DCX-IN-FQP_9".
Jesperwe said they confronted this salesperson about the cables. They then lectured the salesperson on theory. There’s no indication a question was asked with an honest desire for the answer.
When a conversation becomes a confrontation nuance is the first casualty. Jesperwe and the salesperson may have been participating in completely different conversations from their perspectives. Without more information I can’t draw a further conclusion beyond jesperwe participating in (or instigating!) a confrontation with a retail salesperson.