Lockdowns are not the same as school policy. Many schools were entirely remote or hybrid entering the 20-21 school year. Fully remote school was tapered over time, but a huge number of them remained hybrid through the end of school year.
In discussion, most people associate lockdowns directly with the wider Covid response.
The subhead expands and explains, drawing in the "world of masks and remote health visits has created a generation at risk of social and emotional difficulties".