You've been very judgmental.
Funerals very rarely bring out anyone's best sides, and even then, so what?
As a guest, it's your role to be as kind and supportive as you can be. Going up to them and giving a veiled accusation of being late, then judging them for keeping themselves to themselves at the wake, isn't part of your job description.
Your job is to attend, dress appropriately, remember your friend, sing heartily if there's any hymns, give a robust "Amen" at any prayers (even if you don't believe), offer your condolences to the family, have your share of the food and drink, spend some time politely looking at any photos or mementos that might have been laid out, offer your condolences once more, then politely take your leave.
Save any gossiping about the family members for a more private space.