One reason is that inflation has a lot of inertia, because inflationary expectations drive more inflation. A strong labor market drives up wages. When not matc

One reason is that inflation has a lot of inertia, because inflationary expectations drive more inflation. A strong labor market drives up wages. When not matched by GDP growth, those wages increase costs, which cause workers to demand higher wages to keep up with those costs, and so on. The cycle needs to be broken even if there is short term pain for workers.