I disagree. Well, I agreed with what Linus did but not the general idea of your post. If too many people in the group actively push against new people then the group suffers. It may appear no harm lost in telling the guy that made a suggestion that's already been made several times to go away because he's whatever the current popular insult happens to be, but it does cause harm such as reputation. The guy making the suggestion most likely does not know he was not the first to do so. Being nice about it may encourage him to try another suggestion he may have in the future and possibly benefit the group. If you just insult him then you're just telling him not to bother again, which is detrimental to the group.