Interesting. Is it common for anime adaptations that alter this much?
What's shown so far in this thread are fairly mild alterations; it's common for Japanese anime adaptations to be altered and censored far more excessively. Altering the brutal depictions in an original Seinen manga broadcast on late-night Japanese television into a hollow vestige of its former self tame enough it won't turn some Japanese lady's poor little Yamada Tarou into a sex-crazed brute of a man. The Japanese adage 'anime is for children' rings true cause all anime is censored to be safe for children (though more like Safe For Women; SFW).
Not meaning to veer the thread off its topic of the OP anime in question, but my favourite case of differences in manga and anime is Kaishaku's UFO Princess Walkyrie (円盤皇女ワるきゅーレ). Despite the manga being a shounen manga serialised in one of of Enix's manga magazines, the anime's censorship turns the plot that's suitable for children in paper form into an alternate universe where the plot beats happen but for completely different reasons. My memory is fuzzy, but the head catgirl maid, Sanada, in the anime turns all of the local human residents into catgirls in the anime to ensure Kazuto remains faithful to WaruQ as she approves of their relationship, but in the manga, Sanada accuses Kazuto of being a paedophile and creates the catgirl army to brutally murder him like a pack of black people during an American riot, crushing his skull into the road pavement. Instead of childishly impersonating Kazuto to make WaruQ hate him while he's still alive in the anime, in the manga, Raine stuffs Kazuto into the bathhouse boiler so he burns up like Mrs. Lovett from the Sweeney Todd theatrical movie, and then impersonates Kazuto so she can more effectively ruin his reputation by sexually harassing and groping women (WaruQ thinks this is funny and starts copying Kazuto-Raine's sexual harassment). Kazuto dies so much in the manga, Kaishaku even turns all the ways Kazuto gets murdered into a death count gimmick he showcases under the cover jackets with only a single volume not having an instance where Kazuto dies horribly, so there's a victory dance celebrating Kazuto's survival.
I mentioned this in another thread, but the Japanese are just as much—or far more—disrespectful when it comes to their own localised translations and adaptations of another person's work. If someone tells you something is OK in Japan but not legally OK in the United States, they're lying to justify their own insecurities. As far as laws are concerned, 100% of any current media in Japan is allowable in the US, but the same isn't true for things from the US to Japan, or even within Japan itself since no one understands Japanese laws, so each platform has their own interpretation and censorship policies (what you're allowed to show on Sega Saturn is different to what you're allowed to show on the Sony Playstation 2; what you're allowed to show in Shounen Champion is different from what you're allowed to show in Shounen Gangan).
In summary, alterations like this are very common in Japan.