You don't by chance own a car dealership do you
Funny you shoud 'joke' about that. No, I don't... but my brother is a Service Advisor at one dealership and my dad is a Service Manager at another (both Chevy).
I guess that gives me a different outlook on dealership service depts. They a-l-w-a-y-s get a bad rap, albeit
sometimes justifiably so, but I guess the reason I have to defend them is they're constantly in the shaft position of being the middleman between the bitching customer and bitching corporate. Naturally if there's a discrepancy between the two, they're going to cover their ass and err on the side of caution towards the business/corporate interests. Just realize that chances are, they've seen every warranty claim in existence... and it does them no benefit to reject your warranty request as long as Mazda corporate will honor it (either way the dealership gets paid).
I should note, that most techs/advisors/etc
do care about the customer when there are actual issues that need resolved(this is an example of that)... but when you come in complaining of rattles or other nitpick crap, they will roll their eyes and laugh at you (lol2)
So yeah, bottom line, definitely fight it and see what you can get out of it, but don't think they're crooks if they say no. EITHER WAY, yes, you NEED to get the ATF changed... this is not something to put off.