The keywords listed under Optimization > Content Keywords are there on the basis of prevalence and so, as you rightly say, bits of boilerplate text that appear throughout your content will show up high on the list. One of my sites has a forum, so words like "post" and "location" are prevalent.
These words aren't important from an SEO perspective, either to you or to the search engine. Hopefully, at least a few terms relevant to your site's topic are on that list, in which case there's no problem: if not, you might have cause for concern, and that warrants a question of its own.