Again, if Final Fantasy XV was 2 hours long, had no replay value, no music, was glitchy as hell, had a terrible battle system filled with technical issues (think The Last Remnant but worse), and had a story filled with inconsistencies and plot holes, would not liking it no longer make you a "true fan" of Final Fantasy? No.
Just like how you can still be a "true fan" of Final Fantasy if you hated XIV because XIV WAS legitimately downright atrocious.
And a lot of people feel like XII, XIII and XIII-2 don't feel like FF's, or that something about them isn't as good as the rest (the writing, the battle system, the story, whatever), so does that make them not "true fans?"
Give me a break. Grow up.
"Dyin' is easy. It's the livin' that's hard..." Grim Reaper, Maximo vs. The Army of Zin