here is proof, i double checked it now to prove to myself i'm not crazy (at least on this topic)
for one thing, nobody has made it clear there are two versions of role manager. owen winkler wrote an older one that does not work with WP 2.0 versions. The German link above is the correct one.
I uploaded the German coder's version, and created a new role with the only capability of reading. Logged into it, yep can only access dashboard and profile. Great.
I added the capability "edit posts", note i did not add the capability "edit others posts". So I have "read" and "edit posts" as the only two capabilities. I double checked in both the role manager for this new role capabilities and in the specific test user/long for these two capabilities.
Logged in under the test user, lo and behold I have access to write, manage, and COMMENTS!
per http://codex.wordpress.org/Roles_and_Capabilities#edit_posts
this capability is only supposed to allow ability to edit your own comments, not others.
I quote:
<i>
Manage->Comments -- meaning: "show post"-link; "edit post"-, "edit comment"- and "delete comment"-links only on own posts since edit-comment.php (http://trac.wordpress.org/file/trunk/wp-admin/edit-comments.php) looks for "current_user_can('edit_post', $comment->comment_post_ID)"'
</i>
Perhaps the issue is this test user has no comments, and so it may not be able to show any and so errors by showing all? If so it's not working correctly, it should show a no comments, not everyone's.
This test leads me to believe wordpress has an error in the core code that needs to be fixed in the next release.
Please point out what I'm doing wrong and what an idiot I am, I beg you.