difference between studio and hifi speaker

why do audiophiles dislike studio monitors and vice versa?

I often read that studio monitors are perfectly flat whereas hifi speakers are deliberately designed with a sagging response.

is that the only difference that explains the difference in sound?

I have found all studio monitors to be unrefined, harsh and unpleasant. However ive been told that is because they are designed to be extremely accurate and honest rather than beautiful.
 
whats the truth?

kef blades are hifi speakers. They are flat. But ive not seen them being used in studios.
genelec is a popular speaker in studios but rarely mentioned in the audiophile community.