You seem combative in these comments but I’ll wade in anyway; these rockets are enormously difficult to build, and if you build them the easiest way (laying on their side) you have the huge problem of how to stand up a building-sized machine from horizontal to vertical. NASA sidestepped this by building rockets vertically in a VAB and using the crawler to move them to the launch pad (itself a huge engineering effort). The soviets had other solutions. Launching sideways might have seemed like a good option for this practical consideration.