I don't think this is an honest assessment. From your own source, Boeing's "Defense, Space, and Security" segment draw 39% of the company's revenue, while it's "Commercial Airplanes" segment accounted for 32% of its revenue.
I don't think that there is a single company on earth that would describe the source of a third of its whole revenue as something they do "on the side". Moreso when the top segment is barely over 5% larger, and is comprised of a coarse agglomeration of activities that may or may not be all related.