Just because you don’t believe in it doesn’t mean “It doesn’t sell”. The vast majority of Arabs believe that we are one nation, regardless of whether they believe in unity or not. Every survey by the Doha Institute shows this every year.

As somebody who can be considered Syrian

You must be diaspora. Diaspora Arabs are often isolated in the community of their local dialect and unaware of the bond that ties all Arabs together.

the language I speak is more different to the language spoken in Algeria than Norwegian is different to Danish

This is irrelevant. White people don’t set the standard for national identity. Look at India, a single country with a population much larger than that of the entire Arab world and 22 official languages.