Board Thread:Monster Discussions/@comment-26942270-20160219134015/@comment-25285745-20160220031735

Destoroyah was already aggressively attacking people before they attacked him. When the juvenile Destoroyahs showed up and started destroying buildings, a SWAT team was sent to investigate. The juvenile Destoroyahs took that opportunity to stalk and brutally kill them even though the soldiers had no way to harm them without flamethrowers or explosives. Then when the Destoroyahs finally merged into one, Destoroyah started destroying everything in his path. When Junior showed up, Destoroyah attacked him and tried to kill him, then tried to attack the chopper with Miki. When Destoroyah reached his final form, he could have just flown away. Instead, he found Godzilla and Junior and decided to knock Godzilla over while he was reuniting with his son, then killed the completely helpless Junior right in front of Godzilla. Then he attacked Godzilla on multiple occasions while Godzilla was grieving, and in the part where he drags Godzilla by the neck, Destoroyah very plainly appears to laugh.

Then if you go by non-film media, Destoroyah's even worse. The video games say he seeks the total annihilation of all life forms in existence, and in the comics he hunts down and brutally kills an entire group of humans. Toho clearly wanted Destoroyah to be a villainous and demonic creature, hence his design. If Destoroyah had no evil intentions, he could have simply avoided conflict and not attacked every single thing he saw.