Is China dumping cheap spokes on America market?
The short answer is, "Find a dealer you trust."

Whether what he told you is right or wrong, you clearly believe he is having you on.

That will not result in a good relationship, no matter whether he is scamming you, or not.

Most likely, he is either poorly educated on the cause of the spokes breaking, and is having difficulty explaining something to you in an effective manner, and is therefore making stuff up, or he is having you on.

Either way, move on.