Periodically, in Blogger Help Forum: How Do I? , we see a naive query. How do I report a person who posts nasty things, in comments, on my blog? And the unfortunate response here is You can't report unwanted comments. There is no comment censoring agency. Blogger considers comments to be protected as freedom of speech. Outside of moderation for spam - which is a collaborative activity - comments are up to you, the blog owner, to treat as you please.
What Blogger won't tell you