This is one of those cases where they saw a really cool manga and thought "Hey, that'd make a good anime", and were wrong.
Horribly, painfully, dreadfully wrong.
I think part of it is its episodic nature, and part is the level of detail that you just can't really go into with an anime without massive costs. In manga, QUALITY background characters can be accepted as "unimportant", while a more serious tone is added to the foreground. It could also be treated as comic relief without being fucked up by animation. Just doesn't look right, you know?
Same with the creepy cackling animal people. In manga form, it's lent a certain class, it feels more like it's just stylish rather than fucking stupid.
All that really matters is that the manga is superior. Read it, grab the OP and ED if you like them then drop the anime like...
like I just dropped the ball? I guess?