Not being on Twitter is being called "silent"? Is that the yardstick for not being silent?
I'd rather communicate outside of giant echo chambers and text length limitations and engagement optimized (a)social spying media, with real people and speak out there. With family, friends, the neighbors or the neighborhood, for example. Outrage about whatever on Twitter will not help anyone much, except Twitter.
I would also guess, that more than 25% of people in the US vote in elections. Surely that is not "being silent".