Discarding flat design as 'abomination' by 'idiots' is rather missing some of the wider design context.
Take a look back as Swiss design from the 50s, for example. Lots of use of minimalism, bold colour, simple typography (Helvetica, even!). It's remarkably similar in some senses; one of the reasons it became popular was because of the perception that design had become fussy and overburdened by ornamental detail.
I think we saw the same process of design evolution with modern flat designs. There was certainly a perception among some designers that it was difficult to build modern interfaces in part due to the cruft which had been accumulated over the years. Look at an iOS 6 device, for example; even though it's been only a few year, it looks utterly baroque to my eyes now. Needless lines, textures, gradients and shadows that obviously served a functional purpose at one point, but with that purpose gradually diluted as the functionality and interaction patterns of software evolved. Building to modern requirements – with things like touch-oriented interfaces and responsive applications – can become much more complex with these constraints.
The thing is, design approaches will evolve over time. Designers, developers and UX folk will continue to tweak and adjust designs to offer a better experience. It's not always going to be right, or even visually appealing, but it's also a field that experiences constant change. Look at Google's Material, for example – it's not simply flat, but involves the use of animation, subtle gradients and shadows.