What makes a fleet a fleet isn't a video, it's that it's transient. You can make a text fleet. Or could.
If you've never used a fleet and have read the post, you can use the text from it "Most Fleets include media" to conclude that there exist fleets that do not include media. Video is a form of media. You can then conclude through pure syllogism that fleets do not require video.
If you've never used a fleet and have read the post, you can use the text from it "Most Fleets include media" to conclude that there exist fleets that do not include media. Video is a form of media. You can then conclude through pure syllogism that fleets do not require video.