Te be quite honest, there are those on /a/ who see a lot of Umaru in themselves (even though they won't admit it) and that is likely why they dislike her.
At the end of the day, Umaru does not want society to be divided. She doesn't want us to be miserable. She wants us all to come together to enjoy our favorite snacks and geimu so that we may find peace. Is that so wrong?