You are vastly, vastly mischaracterizing government shutdowns as “free holidays.” Shutdowns due to lapses in appropriations by congress are extremely traumatic for ordinary government workers. It’s not as though you can just go on a trip while you wait for the government to re-open, as you must be ready to report the next day if appropriations are made. There is absolutely zero guarantee that back pay will be paid, despite what might have happened previously. Even if you wanted to work pro bono, you are forbidden from doing any sort of official work, even checking email, during a shutdown. In all, it’s stressful and morale crushing, and incredibly wasteful, as huge amounts of time are spent preparing for a shutdown and then spinning back up from it. To give just one example, at government science labs, experiments must be stopped, and any field work must cease and everyone must come home, which can ruin a big experiment that may have been years in the making. Calling it a holiday is flat-out false.