Hate is a strong word. I am ….meh....just never found a use.
I've had 3 of them
The best one I had was a paiste signature 20" ….but...just never fit in. I would bring it to gig and never hit it.
I think (this is just opinion)
I think some drummers "Identify" with a cymbal and it becomes part of their "signature sound"
Roy - Flat Ride
Bill Stewart - Bill Stewart ride/old k trashy
Jack - Dry
Al - SCDR
Billy Hart - 3 20" cymbals ….like different "paints"
Paul Motian - SCDR/OLD A....but with big sticks
Brian Blade - 24"
I could go on...
So yeah if flat ride is "your thang" God Bless you
In certain idioms, they're very useful. Maybe not on most top 40 gigs, but for anything requiring wide dynamic shifts or the ability to play under acoustic instruments, unmic'd, they are so much easier to control than say, a 22" Paiste Masters Dark Ride. And they can be articulate enough to use on fills, almost like a smaller tom.
I have 4; 20" blue label 602, 20" Orion, 22" Meinl Byzance with rivets (love it!), and a 20" Sabian DeJohnette 2 series. I like them a lot.
I bought one back in the 70s, I believe it was Zildjian, at the recommendation of a drum shop owner. I forget why he recommended it, and his other recommendations led me to make some wise buys, but I never bonded with the flat ride. After trying it for a few gigs, I got rid of it and never had the incentive to try another one.
Maybe if I tried one again I would change my mind (I won't go so far as to say that I hate them) but flat rides don't interest me. Been there and done that.
20" A Custom 2000g (low pitched sparkly) (sorta wobbles)
20" Bosphorus trad 2290g (med pitch kinda Turkish) (sounds American)
20" Avedis 2650g (Beast bomb strangely Star Treky) (was discovered in my buddy's Grand Marquis trunk. He gave it to me. Free.)
22" K eak (love at first tap realized later it didn't have a bell)
20" Istanbul trad. (sounded like an Avedis)
18" fo602 Paiste (broken but amazing)
18" K Custom (would not remain level on stand. Flopped like a fish out of water)
20" Sound Creation Mellow ( never called a flat wore it's name in shame inaudible the one gig I remember using it. really. inaudible. I was 2ft away)