Different bullets for different applications.
Projectiles are also getting better and better, and its getting harder to make a bad choice.
There's also a lot of personal bias and to a wider extent discipline specific bias for specific projectiles, based on what is winning. I like Bergers because historically they have worked great for me, and have been very easy to develop a load for. For other people that may be Sierras, or Lapua (I've had great luck with Scenars), Hornady, etc.
For a lot of what us shooters on SH do, Hornady works just fine. I've had excellent results with Hornady out of some barrels and chambers. Other barrels and chambers don't seem to like them as much. While not my first choice, its silly for people to just completely dismiss Hornady - lots of other people have great success with them, especially with the type of shooting we on SH do.