You misread the image. Its income tax only that they don't pay. The reason they don't pay income tax is that their income is too low. For example, a guy who works all his life in low paid jobs, retires at 70 with no savings and lives on his social security.
The lousy scumbag thief! What right does he have to keep his income so low that he pays no income tax? He should be forced to work at a productive job! What gives him the right to be a parasite on society and work those low-paying jobs that should be reserved for children?