This is one of those things where I feel like expectations are very much being misplaced.
If you're talking about world exploration, or story, or just going through adventures in content, whatever...then yeah, you have a point that a "walkthrough" might ruin the experience.
But in terms of just raw class performance, being told that X->Y does more DPS than Y->X isn't some kind of spoiler. It's just telling you what works. Like, hey, Fire spells do a lot of damage, so use them as much as you can. That's not stealing your personal creativity or ruining your adventure of something, it's just...what the numbers say.
I feel like there's a lot of this in XIV, where some people are just vehemently opposed to concepts like performance. It's almost like some kind of backlash against WoW specifically (as they often reference WoW directly in these complaints) and they think that XIV is a game where none of that exists and it's just not true.