AITA for snapping at a grieving person

I know I've made a mistake, a rather terrible one at that. I've aplogized for it since, and all has been resolved between me and the other grieving person, they will remain anonymous.

Recently I've been going through some hardship, my grandfather is bedridden and dying due too a cancerous growth on the back of his neck. It's been hard as he doesn't even recognize me anymore, and I've been dealing with it alone; I didn't want to burden anyone with my problems again.

In order to alleviete some stress i enjoy playing some games with close friends, normally building games and the like. Me and my online friends have known eachother for close to 5 or 6 years, we share this small community gaming server which has about 150 people in it. In this server is a venting channel as well as some rules about not pinging everyone.

After one of these sessions I get a notification, about some strangers grandfather dying in the server (it wasn't in the venting channel and I don't know why I was pinged) but in that moment I failed; I snapped at the other person. Instead of being there to comfort them I chastised them for pinging everyone. I didn't insult them or berate them, just told them to not put it in main channel and don't ping everyone.

It was a cold and cruel thing to do, the only reason why I did that was because it reminded me of my own grandfather and how just kinda helpless I am too it, it just made me angry and I took that out on a stranger who didn't deserve it. I later did aplogize to them about it, I poured my heart into that apology and it's a moment I deeply regret.

However due to my actions alot of my closest friends of many years have cut all contact with me entirely. It's their choice, but I think their response is unjustified/extreme. This is one of the only times I've ever snapped in front of them and my coldness was directed at them either, I also made amends with the person that I was cruel too. So I'm confused as to why they have cut contact on the strangers behalf? I dont know if I deserve this or not.