He seems to be talking about the harsh way some people react to celebrity suicides. They are not lenient opinions, and they're convenient ore easy for someone who hasn't dealt with suicidal thoughts, severe depression, or other mental disorders to have.
They get only a fraction of love, because of the huge magnifying glass they're under from the public. The general public's view of a celebrity is limited, so they only see what they have on the exterior instead of the inner turmoils they may be dealing with. They've got "everything, " so it's hard to sympathize with their depression because the public only sees privilege.
"I'll mourn for a kid but won't cry for a king" compares the unquestionable tragedy of a kid's suicide, with the confusion of why a celebrity would throw away everything they've got.