This is a Catch 22. If Sony held the event, they'll most likely get a lot of shit for being insensitive, not caring about lives and putting video games ahead of anything else. I've personally seen numerous gaming companies put out their statements with regards to current events and Sony is on board as well.
If Sony doesn't hold the event? You have to deal with the blowback of people that were looking forward to some good news this week, people that need some form of an escape to cope with the shitty state of our country, etc. But also, the reveal would be overshadowed by current US events.
No matter how you look at it, Sony is trying to foster good will to masses from a horrible situation and that means delaying the PS5 reveal. I'm very eager to get more information on this as well but I can wait.