My initial read was OP specifically chose obtuse phrasing in order to cast a malicious tone on the situation.
There is no positive attribute to describe something as “slithering”. Not only does it carry negative connotations, it also poor fits the patients behavior.
So
Purposeful use of negative phraseology.
Incorrect usage of negative phraseology highlighting the willful choice of such words.
Perhaps the OP is a poor English speaker, if that’s the case, He should not be defended, this negative reaction is a social teaching aid.