Ryan Counsell, 28, a Muslim convert from Nottingham, denies four charges, including having possession of an al-Qaeda bomb-making guide.
He told Woolwich Crown Court on Tuesday he downloaded the videos due to a "business interest".
He said he wanted to create a "catalogue of propaganda" online.
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The married father, who worked at the Hyson Green branch of Asda in Nottingham, told the judge he downloaded videos so he could analyse and write articles about them.
The jury was shown several of the videos, including footage of explosions and material explaining the structure of the caliphate (an Islamic state).
When asked to explain why he watched this video he said it was something he found "interesting".
He said its "main purpose" was "to show how Islamic State claim to organise themselves".
Asked why he had named a folder of material on his computer entitled "alleged Jihad", he told the jury: "It is something that I do not believe they are actually performing with a genuinely religious motivation.
"I believe it's just a form of terrorism, it is nothing to do with the religion. That's why I titled it alleged Jihad."
Counsell is charged with preparing acts of terrorism by obtaining information about Islamic terrorist groups in the Philippines, arranging to travel to the Philippines to join and fight for an Islamic terrorist group, and purchasing equipment and clothing for use when having joined such a group.
The trial continues.
A supermarket worker accused of trying to join a terrorist group watched Islamic State (IS) videos to learn more about propaganda, a court has heard.