I'm guessing they hate it because the main character shifts in the manga vs anime from a middle aged widower to an (at the start of the series) annoyingly ideal

I'm guessing they hate it because the main character shifts in the manga vs anime from a middle aged widower to an (at the start of the series) annoyingly idealistic teenage girl. Although as the anime progresses, it doesn't focus nearly as much on her, shifting to one of her coworkers... Personally, her aggravating her coworkers is hilarious, and if you've ever had a late-teens/early 20's intern/employee in your workplace, you've been there, and perhaps you remember being like her - very pure and simple in your ideology and worldview. People who don't stick it out more than a couple of episodes don't get to see her character development and its message to both young idealistic folks who grow, and their cynical adult coworkers who help them achieve that growth. It's a wonderful 'soft' scifi anime with good production values and a storyline that avoids the typical anime bullshit ("enemy bad, us good...but....SURPRISE, enemy not bad!", "teenager drama involving kids who are the only ones who can save the planet/japan from aliens", and "deep" plots that are mostly just the writers creating stuff that doesn't make sense and never explaining it, with random plot twists)