I said all of their bitcoin. Coinbase certainly doesn't have all of my bitcoin.

I didn't intend to make a conspiracy theory out of my question.

The question means all of our Bitcoin at Coinbase. He's not making a conspiracy theory out of it - he's asking a legitimate question about whether or not Coinbase has all deposits accounted for or not.

Perhaps legitimate, but not in response to my comment.

That's a rationalization around the original blaming statement you made. You asked how we should know if they are secure. He said how do you know they haven't been hacked already? Both legitimate, up to the point you said he was making conspiracy theories.

I think it's a jump to say "hacked already."

I assumed he was talking like they had just spent the bitcoin (Mt Gox stylee). Even if they were hacked, I would expect Coinbase to disclose that information--to presume that they've been hacked, lost bitcoin, and are hiding that from everyone is a pretty wild theory in my book.

You can make sure that Coinbase has none of your bitcoins if you transfer them to your own wallet as soon as possible.