So I know a few people who work for SpaceX (fewer than who work for Telsa), and they didn't have a harder time getting in than any other fashionable tech company. They had engineering degrees from the right schools and they acted like they read TechCrunch, Wired and Fast Company regularly without either hurting themselves laughing or loosing their lunch, and they got the job. If I had deep pockets and wanted to sabotage SpaceX I wouldn't do it by having someone fire a missile or something, I'd find an employee in the right position smart enough not to have dunk the kool-aid and senior enough to be tired of it and pay them never-have-to-deal-with-this-bullshit-ever-again-plus-worth-the-risk-of-jail-time money to throw a wooden shoe in somewhere. Much more expensive than $38k, but much more likely to go unnoticed.
I also know a few people at SpaceX and I don't disagree with your assessment of their security. At the same time, you're arguing that avoiding a paper trail through whatever unknown internal security and document control is going to be easier than taking some sort of pot-shot from outside the control zone of a launchpad. The difference might be that I've been at the edge of the control zone of a launchpad and can say with no quaver in my voice that it's eaaaaaaaaaaaasy to get as much big bulky crap as you could possibly want right up to the perimeter.
I base my assumptions about internal security on a friend from high school who works at Daimler as an engineer now, who has been justly praised for her efficiency because, unknown to her employers, she gets her job done by 'sploiting her way around their draconian but incompetent IT department and avoids hoop-jumping and paper trails entirely. I know this because I've provided a few pointers for 'sploiting her way around The Process. She, unlike everyone else I know of our vintage, still cares about the best interest of her employer. She's both morally superior and more a sucker than all of us, but that's beside the point. I don't believe internal security and document control would be much of an obstacle at all.