This is actually quite surprisingly because messages submitted through those forms will not be published, unlike comments. Comments spammers usually seek to generate traffic to their own websites or those of their associates and hence need their spam comments to be public [comment spammers are not interest in the site-owner but in his visitors].
The contact forms are meant for people to contact us privately, and hence are not published on this site. Therefore it is pointless for spammers to submit their “comments” through those forms. We will not reply to such spam reactions and they are deleted at first instance.