Nickhere, I can't answer for those other fellas, but I can try to explain to you why I would agree with the statement (God, if he exists, is not a good god).

Strictly speaking, we have only three sources to look to, regarding God's goodness: the Old Testament, the New Testament, and the world we live in.

The Old Testament is full of horrific stories of God not being good. He directly destroys cities, men, women, children, animals, again and again: Sodom and Gommorrah (remember Lot's wife? All she did was look), the firstborns of Egypt (including firstborn animals, and after repeatedly 'hardening Pharoah's heart' so he will continue keeping the Jews in Egypt), the Flood (every living thing).

He indirectly commits genocidal and homicidal acts by having the Jewish Tribes do it for him (kill all the men and boy children, and the women, save the young virgin girls for yourselves).

He likes 'testing' people. He tests Abraham by cruelly letting him think he must sacrifice his own son. He tests Job by, among other things, killing his entire family - all for a wager with Satan.

In the New Testament, he invents what to us non-Christians seems a horrifying plan of redemption: he inserts part of himself in a human body and allows himself to be publicly tortured to death. This bloodshed (horrible, but no worse than and not as bad as many of the deaths that have happened to multitudes of mere humans) he wants remembered and commemorated in a somewhat cannibalistic fashion and this will somehow cleanse our sins. This may have made sense 2000 years ago, but doesn't today, to me.

In the world, we see no correlations like good people get good things, bad people get bad things. God told us prayer had some point, that we would get help from prayer: patently untrue, as anyone stuck praying in a church in Rwanda a few years back could testify, or in fact anyone who's watched their child suffer and die.

In the world, that this good god created, we see even nature is cruel: carnivores must kill, prey animals are killed, creatures suffer, eat their young, die in terror, starve, etc.

It's difficult to see this kind of deity as entirely benevolent - wrathful, capricious, vengeful, yes.

I am aware of the variety of Christian Apologetics for these things, but I find them pretty weak.