Their hate comes from the casual crowd who can't effectively deal with the slivers' exponential power creep. The only thing that can take out a sliver deck is a good board wipe, but other than that, it'll beat out a army of green fatties most days of the week due to the tech it provides.

Are slivers fun?

Playing slivers is a lot of fun though, everything you do makes much more impact on the board than most other decks.

Are sliver decks fun?

Slivers are a very fun archetype to play, but their biggest problem is retrieval and board wipes. I always run a few 'fetch all from graveyard' cards in my deck like Patriarch's Bidding and Creeping Renaissance.