One word for repeated acts of sick behavior?

Solution 1:

depravity, with the plural depravities:

moral corruption; wickedness.

Your sentence would be:

'...provides an environment for them to commit their depravities.

Solution 2:

A few suggestions:

'...provides an environment for them to commit their attrocities'

'...provides an environment for them to commit their offenses'

'...provides an environment for them to commit their brutality'

'...provides an environment for them to commit their savagery'

'...provides an environment for them to commit their barbarity'