Bomb threats have been disrupting classes at close to 20 predominantly Black universities in the United States. After a handful of threats on Monday, the first day of Black History Month in the US, more than a dozen campuses went into lockdown over new threats the next day. Tensions are also high over an ongoing battle on the public school teaching of critical race theory. It says racism is not just the product of individual bias, but embedded in America's legal systems and policies.