How to hide a field in a comment in hook_comment_view programatically?
hook_comment_view(), along with most of the other entity view hooks, are typically used to add properties onto the entity object.

If you read the source for comment_build_comment(), $comment-&gt;content[] has already been built up by the time the view hook gets invoked.  So, messing with the field directly has no effect at this point.

You want to implement a template_process_comment() in your theme, or you can implement a module (which technically makes it an instance of hook_preprocess_comment().

Implement this, and then dpm($variables) inside it.  Figure out what you don't want, and then unset() it.  If the variable is printed directly from the comments template, this is is directly in $variables.  If it is in the content section, then unset the proper key in $variables['content'], which is a render tree.