Judgement versus Mercy

For judgment will be merciless to the one who has shown no mercy but mercy triumphs over judgment - James 2:13

When I hear people say that Michael Jackson (or anyone for that matter) is going to hell, my eggs start cracking and my blood pressure registers in 3 digits, like 500/200.
Only God knows the person's heart and if that person has accepted the work of Christ on the cross and trusted Christ as his/her Savior to make him or her righteous before the judgement seat of God, then he/she will be saved and will spend eternity with God. Of course we can judge, or how else can we be discerning of what is evil and what is good? But judgement about salvation is strictly of the Lord God.