It doesn’t matter. Finland is often included when talking about Scandinavia, which in modern days just makes sense culturally. There’s no value in trying to cling to the ”histprically correct” meaning of a particular term. Languages evolve, dictionaries change.
That mindset will make you a grumpy old soul. Language is dynamic, not something you can force upon people. From every mouth to ear (or screen to eye) the word is interpreted slightly different.
I mean the original meaning of the word Scandinavia certainly doesnt make sense anymore:
1765, from Late Latin Scandinavia (Pliny), Skandinovia (Pomponius Mela), name of a large and fruitful island vaguely located in northern Europe, a mistake (with unetymological -n-) for Scadinavia, which is from a Germanic source (compare Old English Scedenig, Old Norse Skaney "south end of Sweden"), from Proto-Germanic skadinaujo "Scadia island." The first element is of uncertain origin; the second element is from aujo "thing on the water" (from PIE root *akwā- "water;" see aqua-). It might have been an island when the word was formed; the coastlines and drainage of the Baltic Sea changed dramatically after the melting of the ice caps.
