The only people who pronounce the word "bastard" 'bar-stad', which is what I assume you are hearing, are Indians speaking English. And Zazu is definitely not using an Indian accent. He clearly says "young master".
Besides, if you wanted to pick something "dirty" about Disney you could have just used the Simba/Nala dirty porno face bit later in the movie, rather than trying to pick on something that isn't actually happening