Yesterday they said Israel murdered 500 people at the hospital. Today we learn that the bomb hit the parking lot, not the hospital, probably it wasn't 500 people, and that the missile may very well be have been shot by Hamas. The people who repeated this news are not repenting, they in turn blame the news source they got it from, and so no one takes responsibility. But it had serious consequences as millions went into the streets, protesting, rioting, and besieging embassies.
Yes, murder is sin, and you if you can prove 100% beyond all reasonable doubt that the person committed murder then you can judge that they are a murderer. Very few actually do that and rush to judgement. But even if you did all that, do you know the person's heart? Have they turned to the Lord? Have they repented and taken the Lord's blood? Maybe they haven't, but will they before it is too late?
Finally, what good does it do you to judge someone is a murderer? If that is your job, you are the judge or the jury and you do sit through the trial, then fine, you are fulfilling your obligation according to the Noah covenant. But let's say it isn't your job. You run the risk of calling someone a murderer and yet that might not be true in which case you are guilty of slander. Why take that chance. Also, you may be guilty of hate. Christians need to be full of both faith and love. To have faith without love would be what extremists, legalists, and hateful religious people express. I would rather wait until someone is convicted and then simply respond to the judgement others have made.
I call out sin every single day on this forum. There is a difference. I know that the vaccine killed people and should never have been mandated, and probably should have been pulled from the market within six months. But I do not know who is and who is not guilty of murder or to what extent. I don't know who was a liar and who was a useful idiot. Only God knows these things.