People hate because they care. There's some exceptions (like bandwagon hating), but the people who hate on something the most tend to be people who want to like the product.

Exactly, they bought into the promise but the product didn't deliver. If a user expects your product to suck, you won't surprise (anger) them by being sucky.

Yes, it's often more frustrating to see a product with high potential fall flat than a shitty product be shitty.