There are some legitimate reasons to cross-post (problems that span
multiple concerns), and I do agree that the cross post is better than
the multi-post (the same messages posted separately to 3 different
newsgroups).
But posting to more than 2 groups is generally more "spamming" than
legitimate cross-posting because there are different aspects to the
question. Especially considering the minimal differences between
eclipse.platform and eclipse.platform.rcp ... and of course
eclipse.platform.swt is down a level and slightly off to the side :-)