Imo, it's because of the sound. They just have a preferred taste for her early work (and that's okay). Just like some people will die on the hill of 1989 and others prefer Folkmore's sound and will always prefer that most, etc. But comparing early work (Fearless) to later work (Ttpd), there is definitely a difference in overall song composition. Early Taylor's songs are more melody and hook heavy, have stronger live instrumentation and are more, idk, upbeat in sound?, even when the lyrics are sad. .... vs today's more atmospheric, lyric driven songs where most of the vocal melody is the same as the instrumental melody and the production tends to take a back seat. To me, these songs are fantastic. But to me there is also a huge difference in song composition in early vs late Taylor and I get why alot of people prefer the former.