Iran hasn't attacked anyone in centuries. Israel can't even go 10 years without having a war, which they instigated much of the time. Israel also has numerous different forms of WMDs, and has threatened to use them. They pose a significant threat to global security, and as such must be stopped.
Germany's Merkel backs justice minister in dismissal of top prosecutor (DPA)
from the article: Iran installs advanced centrifuges at Natanz to speed up nuclear work