aaq, the shevuos, whether they themselves or the overarching theme chazal teach us about galus, were the idea behind what my rosh yeshiva said.
as to your question about how people could find out without making a huge production with flags etc…word spreads very quickly. all it takes is kids to be told it in schools; they bring it home to parents, emails can be sent out, etc..in a way that doesnt breach the law against non profits endorsing politicians. rabbonim can speak about it in shul on shabbos when theyre not being recorded…it’s really not that hard.