For every rude and arrogant salesman, there are 100 rude and arrogant customers.
This is almost certainly true, however a salesman will meet thousands of customers, while those customers will only meet a small handfull of salesmen. A single poor salesman poisons a much larger pool than even 100 terrible customers. Furthermore one end of that relationship is getting paid and the other is doing the paying, the fact is that it isnt a realationship that has actual parity, so the comparison is moot.