Iran just seized a South Korean oil tanker yesterday to give it civilian hostages as leverage in on going negotiations with South Korea, a country that has never engaged in any form of violence against Iran.
If that was more than an obvious propaganda smoke screen then Iran wouldn't hold the crew hostage.
Iran has also failed to provide evidence for their accusation and did not provide either a warning or opportunity to remediate the claimed polution. Evidence for a crime is of course generally considered a requirement.
They also have a strong recent history of this sort of activity.