The 'miracles' can easily exist alongside his badness. I'm not sure why everyone makes it out to be either/or. There is no universal law that says being both can't logically be true. I mean, there's an easy way to prove this. If I said humans exist and humans are good, you could point out Hitler, and all it does is prove humans are good and bad, and doesn't test whether they exist. And in fact it doesn't even prove that they aren't good, just that they are also bad.

So if someone says "god exists and he is good" and all you end up doing is disputing the second statement... you didn't even touch the first.