What is wrong with people?

This is the second time this has happened in less than a year. What the hell is wrong with these men in MA?

Lowell Man Bites Off Young Boy's Lip

(WBZ) LOWELL A Lowell man was under police guard at a hospital Saturday after he allegedly bit off the entire lip of a 22-month-old boy. Lowell police officials said 26-year-old Thy Chan bit off the lip of the little boy and is now being evaluated at Lowell General Hospital. Police said they were called to 1370 Middlesex Street around 9:30 a.m. Saturday on a report that a child's lip had been bitten off. They said they found the boy covered in blood and were able to recover the detached lip. The boy was rushed to Children's Hospital in Boston where he was being treated. It's unknown if doctors were able to reattach the boy's lip. Police haven't said what relation Chan has to the boy. Chan faces charges of Mayhem, assault and battery on a child and domestic assault and battery. Police said he will be booked as soon as he is released from the hospital.