As you explore the subject of SEO, and aside from the fact that the O can be either mean optimizer (person who carries out the alterations) or optimization (the alterations implemented to the web page), you will discover that the subject of SEO has actually split into two distinctly different definitions.
SEO Definition One:
The first SEO definition (we'll call this: Column A) covers the activity of preparing and presenting a web page in such a way that a search engine is able to measure the relative worth of your web page against various words and phrases etc. that are requested of the search engine by it's clients. This is the starting line for the SEO and this definition has more to do with the basic formation and formulation of each web page. Argue there is more to it if you like, but this is still a decent basic delineation of the first level of SEO.
Before a CMS (software) is publicly released, you would expect that it is compliant with the above SEO definition in as much as is possible. Most CMS software do cater for at least some off page seo enhancement. And enhancement should never interfere with actual content which is of course the most powerful of all SEO tools. Content, like obscurity, is the ace in anyone's hole.
SEO Definition Two:
The Second SEO definition (we'll call this: Column B) extends from the first and includes any means through which bias can be added to influence the natural order of web page selection to the benefit of the website owner. This definition has more to do with the ability of the website's SEO (job description) to further study and apply various eternally changing and evolving methodologies with which search engines use to present their SERPs. This is what you should be getting when you contract an SEO to look after your site and the level where SEO's go into daily battle to pit their knowledge against each other and the various circuits of the internet machine.
And this course, if followed, aims to get you onto this frontline and into the heat of that battle. The purpose of definition two is for the SEO to get quality SERP listings for their client above all non-clients.
And the purpose of the search engine is to get quality SERP listings for their clients. Your aim should be to work with the search engines, not agin them. Be wary of those that sell snake oil along the way claiming it will cure your site of what ails it. Search engines are not obligated to list your site and do ban or suspend sites that use deception or appear seedy in nature without stating this fact.