It could be that maybe she's plain out rude to them, or is inconsiderate, money hungry, or maybe just unwilling to make time for them. Which pop girl is the most undeserving of the unconditional devotion of her legion of stans.
People paid 1000 dollars for a meet and greet and Britney was too scared to even look at the camera straight...and she doesn't even perform for them. She waves her limbs around like pieces of sausage links
Britney and Madonna. I don't think Britney doesn't care about them, it's just her fanbase is largely composed of people that are crazily obsessed with her and she finds it creepy. Madonna is just rude to them.