What is the standard? The Haman curve is just one curve of many. Could be that curve doesn't work for the way my head/ears are shaped.
The Harman curve is one that is specifically designed to appeal to a broad cross-section of listeners. That doesn't mean that everyone will prefer it to some other curve, but on average people will prefer this to any alternatives. From the perspective of manufacturing headphones and/or coming up with standardized EQ profiles, there's no currently better standard than the Harman response.
All that said, you might not like the Harman response, which is fine. I'm actually not a huge fan myself, especially when it comes to their IEM target which I find too thin and too sub-bassy.
I want to hear the music as closely as possible to what the artist/producer heard in the studio
I used to feel the same way, but I've given up on that with both headphones and speakers, and here's why.
1. I don't hear the same way that the people involved in producing the music hear (just one example, I can't hear over 14 KHz)
2. There are multiple people involved in producing music, whose hearing would I be trying to match anyway?
3. Which studio am I trying to match? The recording engineers? The mastering engineers?
Ultimately, I find it more fruitful to think about music at an emotional rather than an engineering level. If the music makes an emotional connection, if it gets my toes tapping or my head bobbing, if I feel something, then my playback equipment is doing its job. The irony of this is of course that even cheapo equipment does this, so our non-audiophile friends are way ahead of us!