QFT.
(... but not just you, all of us.)
Jesus saves (we don't), so those beating anyone up didn't understand the message.
Sorry... I don't much understand any of this. You quoted only part of my post "for truth" - the part about God not being in my heart - then stated "but not just you, all of us." Was this saying God is not in anyone's heart? Then you went on to say "Jesus saves (we don't)" - is this saying that you believe that God isn't in people's heart, but Jesus is? That Jesus saves, but believers don't? And then on top of all of that, you follow up with "so those beating anyone up didn't understand the message." Who is beating who up? Atheists beating up Christians? And is the beating up part what's on their heart instead of Jesus, and that's why they can't understand the message? 'Cause they need to stop beating people up?
I'm just completely confused, and I fear that you will be unable to adequately clarify. If all of this is religious vernacular, or Jesus tech-talk, it will probably simply remain lost on me forever. Which is fine... in the end it isn't going to matter. It just seemed like you were trying to tell me something. This reminds me of that moment from Finding Nemo just after the dad fish got an earful of surfer-dude speak from the young turtle: "It's like he's trying to speak to me, I know it!"
I'll give a shot at explaining and try not to use any Jesus tech-talk. I probably owe you at least that.
You stated ...
I've already looked in my heart, believe me. There is no God there, nor does there need to be.
... let's break this down:
point 1. GOD: A working definition is the all knowing, all powerful creator of everything.
point 2. You state that you went looking for GOD in your heart. You are looking in the wrong place. Any god (note the small 'g') that you can create from inside of you, will not be the GOD (see definition #1). Free Jesus tech-talk ... "idol" = any false 'god' that you create to worship in place of the real GOD.
point 3. You state that there is no GOD to be found in your heart. This was the part that I had 'QFT' and also the part to which I had intended to address the response "(... but not just you, all of us.)". GOD is not found by searching in any human heart, so you cannot find GOD by searching deep inside of you. I cannot find GOD by searching deep inside me. None of the other people you will or have met, in Church or on this site, found GOD by searching deep inside themselves. I promised to avoid Jesus tech-talk, so I will just mention that GOD says in his Bible that the human heart (all of them) is utterly corrupt and incapable of pleasing GOD or even wanting to seek after GOD. Thus GOD will never be found by searching deep inside of ourselves.
point 4. You stated "nor does there need to be." Nothing could be further from the truth. Yes, GOD absolutely does need to be in your heart, and to hear you say otherwise breaks my heart and makes me want to weep. I did not quote this, because this part was not true ... so no QFT. This leads to our problem and my next point.
point 5. I said "Jesus saves (we don't)". Let's strip out the tech-talk and try some straight talk. Once upon a time, GOD was not to be found in my heart. I needed GOD in my heart. There was nothing that anyone could do to place GOD in my heart. Only GOD had the power to do something about that. I can't explain how he does it, people have debated the details for more than 2 millennia. Let me offer an analogy that GOD uses and leave it to you to try and figure out what it means for yourself. GOD says He will pluck out your dead heart of stone, and give you a new, living beating heart. GOD says that your dead heart of stone was incapable of desiring to obey his rules. GOD says he will write his rules on this new heart, so you will not only be able to obey them, but want to obey them. GOD says he will place his spirit inside this new heart to teach and guide you and to guarantee that you will return safely to him in Heaven. No human being could do any of that for me, I can't do any of that for you, nobody else can do any of that for you. GOD is the only one who can perform a dead to living heart transplant. I hope that didn't have too much tech-talk or come across as "nasty" (as described in the OP title).
point 6. I said "those beating anyone up didn't understand the message.", which was directed to the title of the topic and the question about 'nasty' Christians. Since nobody (except GOD) changed my heart, or could have, and we Christians are powerless to ultimately change the heart of anyone else (only GOD can), it really is both pointless and counterproductive, most of the time, to bother arguing with people. There are no commands for Christians to punish any sin or sinner. We are to be ready to explain why we have hope in spite of our circumstances and to tell what GOD has done for us (especially if asked) and we are to correct when Christians say and do what is contrary to GOD's word (but with love and the goal to restore the errant Christian.)
So in summary:
God will not be found in your heart naturally, that is what Jesus came to make possible.
You do in fact need GOD in you, or you are more like a zombie than a man ... a dead man walking.
Only GOD can fix the problem.
Being nasty will not help.
Thank you for listening.
God Bless,
Arthur