Nature really, REALLY hates featherless raptors
imbecile worth less than rotten tomatoes interesting individual thinks very little of the fact that deinonychosaurs, and dromaeosaurs in particular, had feathers like modern birds. Many will deny reality in order to embrace their hot, naked, sexy scaly raptors, by spouting bullshit about them being too big in tropical climates and therefore needing to loose feathers.
Nevermind that feathers actually help to cool the animal down, that birds lack the mammalian brown fat, and that even most tropical mammals retain fur. Nevermind that giant tropical birds also retain dense plumages (in fact, the only naked patches are in the head and in the armpits; otherwise, a dense coat remains on the rest of the body, so dense that ratites can wander around in cold climates), that it is now thought that dinosaurian airsac pulmonary systems and subsequent pneumatic bones might have actually evolved as means of cooling the body. Nope, we will deny reality in order to have huge scaly raptors
to felate and have anal and/or vaginal sex with (they’ll gladly pass through the cringe worthy surgeries transexuals pass through in order to have vaginas worthy of raptor cock).
Perhaps most amusingly, it turns out that deinonychosaurs actually had more feathers than contemporary birds. Troodontids like Anchiornis actually have denser feather coats than the enantiornithes, confuciusornithids and other avialans found alongside them; the same is arguable for dromaeosaurs, although Dave the microraptorine seems to agree, having fluff not only in the snout, but in the feet as well.
Why do raptors have denser feather coats? Not exactly clear, but it must have had something to do with their metabolism. The long bony tails of deinonychosaurs would have easily allowed heat loss, although their probably not the main reason since the animals have dense feathers everywhere.