They never specifically stated all the strikes would be available day one. Or the missions, or the crucible maps. In an expansion, a collection of content, content is included upon release UNLESS otherwise stated. Not the other way around. There wasn't an asterisk on every other thing they showed saying "this content will be available at the launch of the taken King".
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That doesn't matter. Everything they advertised for TTK is/Will be in the game so no false advertisement.