There's a reason to it and I suppose I'm not quite proud of it, because it's the same reason I got thrown into my face by quite a few Percabeth shippers in the past. Then again, I don't plan on stalking Solangelo-fics/pics and posting "Stop shipping it!!1!1!eleven!", so I guess there's the difference then? They may ship it if they feel the need to, but I'll never participate.
But a friend of mine asked me WHY I don't ship it, since I ship both Percy and Nico with quite a lot different people and that's true. So I figured perhaps some of my readers may be interested in my reason too.
As previously mentioned, I don't plan on stalking Solangel