Yes agreed, and its also the reason we have an innocent until proven guilty justice system.
Things can be said in anger, and not really meant. In fact I would wager out of all the death threats made in the entire world, the vast majority are said in anger and not meant to be followed through on. This is why we dont lock people up for just saying things. There needs to be other motives and evidence behind it to show intent.
Unfortunately yes this means we have situations where people are not believed and go on to receieve harm. Humanity has decided as a society that this is less harmful than locking far too many innocent people up by mistake. I do not have an opinion on whether this is right or wrong, but it is what exists for us and created by us.
If you have a better idea for a more fair justice system then go advocate for it, but the whole history of humanity hasnt found one yet.