Why do republicans bash Michelle Obama so much?

She wasn't elected and has no political power. Her only connection to politics is that she's married to the president. I hated George W Bush, but never did I slander Laura Bush, nor did anyone else who disagreed with Bush's policies. I don't remember republicans bashing Hillary as much as they bash Michelle. What has she said that has drawn so much ire? Eat you veggies, take your vitamins, go to school, say your prayers? No one bashed Hulk Hogan in the 1980's when he said the same thing.