I'm not 100% sure on this, but this is the only way I can make sense of it.If neutrinos didn't escape the energy would be the value you calculated. However, because neutrinos leak away from inside the sun, the energy produced, that remains in the sun, is less.
Even if the other particles did gain energy, I don't think the other particles escape, or if they do they escape millions of times more slowly. Hence the (kinetic) energy would stay in the sun and wouldn't decrease the total energy.
This is why you'd talk about the neutrinos instead of the others - because the neutrinos leave and therefore take away some of the energy with them.