I understand about the silicone being bad for wood finishes but, he did not say automotive wax, he said PASTE wax.
I can't help but think that the salesman was just doing his job, trying to make another sale to a new customer.
I used to be a salesman but, I never used false information to get a sale.
Moreover he should have given a reason for telling a customer something that may or may not be true.
Rog