Aiyo you miss the point again.  
The problem here is not about calling people fag because they pronounce it wrongly.
The problem here is calling people fag or snobs because they pronounce it rightly.

Scenario 1
Me: Hey i'm thinking of getting a folks-varr-gurn.
Friend: Folks-WTF!!!! You think you german ah?? Faggot!!

Clear now?

Among friends, i'll just take it lightly, laugh it off.
But when strangers or employees of that particular company?
More so when they're so convinced they try to 'correct' you
True story

Countergirl: May i take your order sir?
Me: Yes, i'll have a whop-per set please
Countergirl: *pause then makes a disapproving face*   You mean you want whooo-per
Me: Oookay