You started a thread criticising the way someone is grieving their dad.
I think starting a thread about someone who has just lost their dad, criticising them going out and posting about it, criticising them posting and tagging their sibling and mum in it, and trying to get other to join in is far more horrible than posters pulling you up on it.
The thread literally had no benefit to you, even if everyone agreed with you, it makes no difference to your life at all, other than to let you continue to be so self congratulatory on grieving the correct way while your 'friend' does it wrong.
The fact is that some people on here will turn to social media for support, and your thread will have made them feel shitty, or make them question whether you're on their facebook and slagging them off.
This is a site people often use when they are recently bereaved, in fact, many years on from the death of our loved ones many of us still turn to MN for support.
You would do well to remember that when criticising others then calling everyone horrible.