[aliensporebomb]

I have a theory now.

Spoiler:

The Studio Deen animators were specifically told to leave those things out
of the story because.

Then they could:

Spoiler:

Encourage people to buy the manga, sound novels, etcetera because
people who got into the stories from the anime' will look online and find
out the full story is available from the manga/sound novels, etc.