When good guy made a mistake, like Uzzah trying to fix the ark, God killed him (see II Samuel 6:6).
However, Uzzah does not seem that evil. I mean, the ark stumbled and he just tried to help.
Then, this site says:
Thus, the Holy of Holies in the Second Temple was an empty chamber, without the Ark of the Covenant. When the Roman General Pompey conquered Jerusalem around 63 B.C., he demanded the privilege of entering the Holy of Holies. When he did, he came out saying that he could not understand what all the interest was about the sanctuary, when it was only an empty room.
Okay, I am confused here. This Pompey is an enemy of Hashem. He came to holies of holies where many high priests have died entering. Yet he doesn't die. So many Roman soldiers would desecrate the Temple and remove all its gold. Yet those soldiers didn't die. Why?
So many westerners blaspheme God on daily basis, God didn't strike any single one of them, and yet Uzzah who only tried to help was smitten.
Why is there this double standard?