The thing is, some people have two concepts of SEO, and conflate the two.
"Everything that improves my site is SEO"
The other is
"Everything I do to try and improve my ranking is SEO"
The first means you claim credit for all good things, whether you meant them or not.
The other means you count everything you do as "optimisation" whether it is effective or not.
Then people wade into discussions without being clear which sense they mean, and lazily switch between the two depending on what suits their current purposes.