Can't comment on anybody's feelings as we all expect (or hope for) certain response, treatment, etc. etc. from businesses we deal with. However, like most here, I believe their answer was acceptable. (I am not a member of any dealer's fun club, including Tradex) Instead of e-mail maybe the OP could call them and discuss this issue in person because e-mails, no matter how written, can be impersonal and taken the wrong way based on our own mood at the moment. Furthermore, I also do not believe there was the need for starting this discussion at all but as I said we all expect certain treatment even if we're wrong. (And one should take the advice from others even if they disagree, especially if 95% of them disagree)
I've purchased several rifles from them and since I do not live far, AFTER COMPLETING the payment, I would put the note for them NOT TO SHIP, and the time I would come over and pick it up myself. Works every time.
And for the OP- I talked to Anthony at one point about the same issue as one of my orders was cancelled due to misunderstanding (he fixed it after) and like you I did brought up the 'regular customer' thing. There was a big sigh and he said if I only knew how many regular customers screwed him over after placing the item on hold with deposit only not to complete the payment for months. That was the reason they changed their policy and now is no more holding anything for anybody. You pay- it's yours. Otherwise...