They are.

We accept that others may make a different moral trade-off. If the U.S. elects to continue testing on chimps, however, then it needs to adopt stricter guidelines. Chimps should be used only in studies of major diseases and only when there is no other option. Highly social by nature, they should live with other chimps and in a stimulating environment with room to move around. And when a test inflicts pain or psychological distress, they should have access to treatment that eases those afflictions.

But part of the poor treatment of the chimps is part of testing. Being infected with a disease, given experimental treatments and undergoing surgery is likely to cause suffering.