SpaceX is a reasonably well-run company. Both they and ULA, for reasons that come with committing to government contracting, have extensive risk mitigation policies in place that prescribe how to continue to accomplish work without unreasonably endangering the health of their workers. It's part of qualifying to bid on critical projects. The U.S. government itself may be stumbling in its response to the latest coronavirus, but the best private-sector companies in aerospace and other industries have playbooks for everything up to and including Armageddon. You may have noticed media reports about various companies in various industries having stockpiled various items, and some conspiracy theories asking how or why they knew to do that. The reason is simply because they have risk mitigation offices whose job is to plan ahead for various catastrophes and quietly take precautions to ensure their ability to fulfill contractual promises under those circumstances. No, I don't suppose SpaceX is working at full capacity, but their ability to continue to execute while under quarantine doesn't really surprise me.
That said, I'm really excited to see a crewed Dragon fly. There are some great innovations in the Dragon and I'm eager to see whether they pay off.