All the information I could find was from greek orthodox web sites and was clearly biased.
What really happened during the iconomachy? Did the military get involved? And why did people care so much about icons to start a war?
Have a look at this Wikipedia article.
In short, there was a current (arguably influenced by Islam) that viewed the use of religious images as sacrilegious, putting it on the same level of adoration of graven images, forbidden in the Old Testament. The military got involved quite a lot: for some reason there were many Iconoclasts in the army, maybe because the bigger part of the Byzantine army came from Asia Minor, closer to the eastern borders and more open to Muslim cultural influence. Constantinopolis and the European part of the Empire tended a bit more for acceptance of icons.
As for why, well, people took faith very seriously in those times. They felt they were living in dark times, what with all the wars and pestilences the Empire was going through. I feel the average person was much more pious than today, so much that theology issues were perceived as vital. Maybe they thought that to be saved they had to get religious practices exactly right?
Ah, theology. Wait until you get to hesychasm. 