What a throwback.
That very split average rating chart makes for interesting reading; suppose it's down to a mixture of Spice Girls fans, people who have nostalgia for the film itself and people who have little to no knowledge of them before viewing. I'm at the nostalgia level, I'd say.
I remember watching 'Spice World' when I was very young and liking it, not sure to what degree but I certainly remember it. I undoubtedly enjoyed their music growing up, entirely truthfully... they did some bangers, don't @ me.
As for the film, which I probably haven't seen in 15+ years, I'll put it this way: Spice Girls as musicians: yes! Spice Girls as actresses: not quite. It's extremely cheesy and the acting is very subpar, but the likeability of Melanie Brown, Emma Bunton & Co. at least keeps it watchable; to me, anyway.
Richard E. Grant commits to his role, while they also got James Bond himself, Roger Moore, involved. There are also a number of cameos. Their music is entwined well, I wouldn't class myself as a fan but I rate a fair amount of their songs.
I can understand if you dislike this, I truly can, but I found it alright to be honest. I definitely wouldn't say it's anything good, or all that close, though. Fans of the group will love it, I presume.