"Your accent reveals your linguistic history, it would be a shame to erase it."
As a proponent of things interesting I must agree: your accent is interesting too.
I think that to a certain extent, it is necessary to make a concerted effort to pronounce words in your new language in the correct way. However, I see so many articles from people wanting to develop a perfect British or American accent. In reality, unless you started learning your target language from a very early age, it will be extremely difficult to achieve that goal.
Besides, your accent is part of your character. As long as you speak clearly enough and are understood, embrace it!
"deep biases about who is considered to "truly" belong and a reductive view of the culture(s) associated with the language."
Guyomar, such biases do exist, and likely accents actually affect people's percetion too... to some extent.
"think sometimes our obsession with accent and sounding like a so-called native speaker reveals "
I'm not sure. Learners may know nothing about the 'biases' common for natives. They also may have no interntion to search for a job related to the language. They may learn a rare or non-prestigeous language. Still an idea to learn how to do ideally something which actually can be done ideally seems interesting and attractive to many people:) When you are wachind dishes you may do it excessively well too:)
"t's much more worthwhile to master the language, including its idioms and idiosyncrasies, and be native-like in that way. "
And harder, by the way.
"I find it a futile exercise to aim to sound like an idealized native speaker."
No, I don't think it is futile. As I say, I think it is interesting and even realistic. But try to look at this as something 'interesting' first:) As to 'idealized', and what does it means... it implies that the native speakers can't tell you aren't by the way you speak. Likely. Of course that people from Paris do not sound like "someone from Quimper or Marseille." is an improtant (interesting:)) detail!
"I'm often left wondering why people so badly want to sound like "native," "
When we don't understand something it is a nice idea to understand it, before judging or seclaring it futile:) Some people don't understand why people do math. Then after we have understood it, we are free not to do this. Knowingly:)