Many hybrids that have occurred were accidental in nature... i.e. the first galah x cockatiel, *many* green cheek x sun conure hybrids, likely caique x mini macaw (illigers?), probably some conure x mini macaw hybrids, conure x amazon hybrids, rosella x kakariki, rainbow lorikeet x king parrot, etc...
People weren't aware that these birds could hybridize, but had them in mixed aviaries or simply housed them together and chicks happened...
Of course, we have the people who see these hybrids and then turn around and intentionally hybridize for profit.... some may do so because it's difficult to find the exact species (or subspecies) of the animal that they have....
And yet many, many more were done accidentally... and continue to be hybridized unknowingly. This falls into the subspecies hybrids.... some people are against hybrids but are okay with separate subspecies hybridizing - eclectus parrots being a great example here! Some may be against eclectus subspecies hybrids, but are comletely unaware of the many other species with subspecies that we have already hybridized... some cockatoo and amazon species, green cheek conures, maroon bellied conures, mitred conures, senegals.... many of these birds have subspecies and we've already hybridized them! People either don't care, or they are simply unaware even if they have been breeders for *YEARS*!