A theist asked me, “Why don’t atheists respond to ‘hellfire and damnation’ preaching?”
I can only speak for myself, from my own personal experience. Here’s my view:
1) You have to establish the believability of the assertion before the threat has any teeth to it — and this has not been adequately established. Without making a compelling case to believe your claim, threatening people that your god will toss them into a lake of fire comes across to those outside your faith the same way it would come across to you if I threatened you that my rainbow unicorn will rise from the bottom of the sea to trample you with its sparkling golden hooves and impale you with its iridescent purple horn.
2) Even if you persuasively establish it, “hellfire and damnation’ preaching still makes your god look like a petty, stupid malefactor, and makes you look like a toadying coward for propitiating him. It’s not appealing to worship such an unworthy god, as a matter of principle.
3) “Hellfire and damnation” preaching undercuts itself; by making your god sound like a psychotic and malicious tyrant, you make an eternity worshipping, glorifying, and serving your god sound equally punishing as an eternity of damnation.