Your intent may be aimed at the administration, but the way it actually is supposed to work is that you're withholding labor from your workplace, which then makes less money, which affects the economy. A one-day strike is really more of a threat that you could do such a thing for longer term and hold the economy hostage.

In reality, if your fellow workers are not organized and on the same page as you, this is kind of an empty threat, since the company can probably fire and replace you without much issue. That would make your one-day, one-person action primarily symbolic, like marching down a street holding a sign. Personally, I don't see anything wrong with calling out sick for this, since you can't actually threaten an effective strike right now.

The real work, then, is to organize your coworkers. If you have a union, you can strike for real.

I would like to join the single-day general strike that is being called for the US this Friday, January 30th

What backing is there for this strike? For example, are there any labor unions, community organizations, and cultural leaders involved like in the recent Jan 23rd Minnesota strike? [Edit: the answer is a pleasant yes! https://nationalshutdown.org/home#endorsers ]

Take a sick day regardless, unless you're going to use them all in the future, but if it's just a few social media posts saying "general strike now!", of which there have been hundreds of attempts over the past few years, without any institutional backing, then temper your expectations. Worker unions exist for us to organize us! So if it's a real strike you want, unionize, and push the union to act.

Call out sick. Use stomach bug as the excuse. No need to let them know the truth.

Your paid time off is your pay, its something you've earned and your employer owes you. Use it.