I'm not trying to defend gigster (broad indemnification clauses are bad news), but if someone framed those questions to me that way, I would also be hesitant to respond to them. It raises the "I'm going to be a handful" alarm. So, I understand why they were hesitant to respond and didn't want to comment on it.
How would you have framed the questions? The seem reasonable to me.
Can developers negotiate the terms of this contract? I was concerned about some of the terms and how they'd affect my other projects."