Yeah, I think someone was reaching with that analogy... I highly doubt that Google's search algorithm actually has the wherewithal to compare sitemaps and then realize that hey, this is just like website #3345AE. It would be a waste of CPU cycles.
An advantage that WordPress might give you and any CMS that has a URL re-writer can give you is keyword rich URLs. Also, a modular CMS provides you the option to add SEO modules for meta tags, XML sitemaps, etc... Do a search for "wordpress meta tags" and you'll find a link to the WordPress meta tag manager plugin. Same thing for "wordpress xml sitemap".
Another advantage you'll have with a WordPress site is that you can update links online in realtime and provide 401 and 301 redirects from within the CMS to redirect links to old pages that no longer exist to new information rather than to "page not found error" pages.
There are lots of SEO advantages to having a WordPress site but the analogy you were given isn't one of them.