This is just not true, but it's an inaccurate perception aided by DC Health not transparently reporting data about case clusters. We know anecdotally about outbreaks and deaths in schools and daycares in DC, but have no idea how big the problem is. https://twitter.com/RebeccaOser_URC/status/1335275498419720195
There's also a strong incentive for businesses like these to conceal the case to create the belief that they are safer and better. That's why government transparency is so crucial.
You can see it in this Post article where the cases we know about are mainly from MD because that's where there's government mandated transparency. https://www.google.com/amp/s/www.washingtonpost.com/local/education/maryland-school-outbreaks/2020/11/20/464a0b08-29eb-11eb-9b14-ad872157ebc9_story.html%3foutputType=amp
Right now we don't even know how many classrooms and students are occurring in person in public and public charter schools, let alone number of cases, so frankly it's deeply irresponsible to be making unsupported and unsupportable claims like this in support of your agenda.