>>212864526
It's not so much about linguistics as it is about politics. Linguists will generally agree that there's a fine line between a dialect and a separate language. It's a linguist who coined the phrase "A language is a dialect with an army and navy."
The Romance languages used to be a dialect spectrum. Rather than have a strict border where, say, Spanish is spoken in one country and French in the other, dialects would change slightly from town to town. The nationalist movements standardized the way they spoke in one part of the country as the national language and labeled other languages/dialects as inferior.