There are certainly differing schools of thought on this, and the postmodernists and many critical theorists might agree with you—subjectivize at all costs! The more traditional approach, however, is through explication. To illustrate, one of my grad profs told the story of a Descartes scholar who had been working on Cartesian philosophy for thirty years when he decided to pursue another avenue of research. His mentor heard of the change and remarked, “what a shame... he was really starting to get it.” Perhaps a bit tongue in cheek (though probably less so than you think), what this fundamentally reflects is the idea that when great minds have considered these others to be great minds—once in a generation minds, to imagine that you 1) understand them from a partial and cursory reading, and 2) might have something meaningful by which to critique them about, rather than to simply attempt to absorb what you can from what’s left of that brilliance (mostly texts), is naught but naive hubris.
I’m not saying you have to be a Nietzsche scholar of thirty years to have anything interesting to say about him; it’s quite clear that many of these “third parties” you’ve referred to can mangle his legacy even with a lifetime of focus on his work. Neither am I suggesting that you should seek to be a Nietzsche scholar or acolyte; your interest in him may very well be cursory, or as a sort of interesting proto-psychology figure to help you understand someone else’s work. But I am suggesting that applying hypocrisy derived from the aggregation of others’ work, and admittedly without so much as a brief exposure to Nietzsche’s oeuvre, while perhaps satisfying to our current state of humanities educators, reads as lazy, hasty, pretentious and naive to me.
And for what it’s worth, I’m not just responding to this little subthread—I read each of your comments on this post. You seem determined to justify what you think you’ve seen. I admire the stubbornness, but I fear you may have been trained to think you can either want your way through the challenges without patience and openness, or else use the reactions you’re getting to write the subject off entirely, likely thinking that you were just never truly understood. I hope not, but if so, no worries friend, I had to have that hubris shoved in my face a few times before I was willing to realize it was there, much less confront it... huh, maybe I’m just talking to myself again.