Don't know if this adds much to discussion, please comment if not and I will remove this post.
In some (European) countries (like Belgium), national television and especially children television networks are not allowed to broadcast (a significant amount of) advertisement. Product placement and mentioning brands is seen as a sort of advertisement, even if the company promoted did not asked for this. The idea is that children cannot properly "defend" themselves against advertisement and furthermore it is debatable whether a publicly funded television network should broadcast advertisements.
If television networks would do so, they have to pay a fine (there are even some hilarious cases where for instance the TV station had to pay a fine because a person they interviewed for the News was wearing a T-shirt of a specific brand).
I can imagine that some fictional shows that target an international audience - like The Simpsons - are aware of such laws and thus make a parody on these brands in order to increase the number of potential television networks broadcasting the show.