I suppose OP **aparente001** wants to know why a user whose post (question/ answer/ comment) was removed due to flagging should not be sent an automated message or manual explanatory message of warning [from a moderator] such as 

>your comment [quote comment] posted on this question [link to Q] at 6pm on 33/13/99 was deleted after a flag was raised regarding its inappropriate content. Kindly avoid posting comments that are derogatory, inflammatory or abusive. Please read the site guidelines [link to **be nice policy**] for more details.

I agree with OP that such a message might be sent to the commenter who was disciplined, **without making it visible to the community.** It might be even sent 2 days after deleting the comment, if the intention is to avoid an escalation of unpleasantness. ***This type of feedback would help an inadvertently aggressive user to modify his/her posts to conform to community expectations of politeness.*** 

However I am sure an intentionally **malicious person** would not learn anything from such feedback, in which case all the 'disciplinary due process' involving moderators mentioned above would be needed to take care of the problem.