Last week I referred to the upcoming 50th anniversary of Betty Friedan's influential study The Feminine Mystique. As it happens, another half-century anniversary will take place next month, one also involving an American woman, but of a much sadder shade: on 11 February it will be 50 years since Sylvia Plath took her life and gained immortality. As her widower, Ted Hughes, wrote in his skin-pricklingly beautiful 1998 collection Birthday Letters: "Fame cannot be avoided. And when it comes / You will have paid for it with your happiness, / Your husband and your life."

Suicide attracts speculation and prurience like flies to rotting food. Most writers who have killed themselves – Ernest Hemingway, David Foster Wallace, Spalding Gray and Virginia Woolf, for example – established themselves before they died. Plath's fame bloomed under the cloud of her death and no other writer's life has cast as much of a shadow over their work as Plath's, and it's a shadow that only darkens. Just as Marilyn Monroe is now seen as the archetypal tragic Hollywood blonde, so Plath has been flattened into the prototype of the mentally tormented poet, the betrayed woman, the tragic literary blonde.

So it's unsurprising that, half a century on, the arguments about her burn with ever-greater fervour, as proven by the extraordinary battle conducted last week in the Guardian's books section between Plath's friend Elizabeth Sigmund and a characteristically combative Olwyn Hughes, Ted Hughes's sister and the literary executor of Plath's estate. Then there are the academics and fans who argue among themselves at least as much as they do with the famously protective Plath estate. Time seems only to have aggravated the emotions, as well as the ignorance. A typical example of the latter came from one British newspaper columnist who tweeted last week: "In her memoir, will Ted Hughes' widow comment on the fact that wives 1 & 2 BOTH committed suicide? And No 2 killed child #thisbothersme." Now, leaving aside that Assia Wevill (Hughes's lover, who killed herself and their daughter in 1969) and Hughes were never married, it is a safe bet that Hughes himself was a lot more "bothered" by the deaths of his wife, lover and child than someone who never knew them, no hashtag.

This is an all-too-typical attitude when it comes to Plath: that outsiders know better, maybe even feel more, than those she left behind, especially Hughes, who is often restyled as the Bluebeard of English literature.

Next month, another biography of Plath will be published, Mad Girl's Love Song by Andrew Wilson, focusing on the early part of her life, before she met Hughes, "reclaiming her from the tangle of emotions associated with Hughes". A commendable aim, undoubtedly, but in doing so, Wilson returns to the old bitter arguments about how Hughes edited Plath's work after her death, asking, with heavy nudge-nudging: "At what point did editorialising mutate into the sinister act of censorship?" Wilson points out that old bugbear about Hughes not publishing all of Plath's early poems and can't seem to believe that perhaps Hughes was genuinely looking out for Plath as best he could posthumously. Few writers would want all of their work published. Hughes's censoring of her journals is given the usual short shrift; perhaps because Hughes is still, outrageously, blamed by some for Plath's suicide, he is not deemed entitled to privacy. (Vera Nabokov burned her husband's letters about their marriage, and fair enough.)

All of this comes back to a bigger argument: who a writer's work belongs to, their family or the public. When Plath's daughter Frieda Hughes refused to allow the makers of the film Sylvia to use her mother's poetry, some were outraged: "She claimed in an article on Britain's National Poetry Day that 'poetry is for everyone', only to deny access to her mother's words a year later when approached by the Sylvia film-makers," fumed one novelist, as though Frieda Hughes's discomfort at Gwyneth Paltrow re-enacting her mother's suicide was tantamount to censorship. Similarly, the frequently voiced suspicion about Hughes destroying Plath's last journal always makes me marvel at the entitlement and egotism of some fans who think that uppermost in Hughes's mind when his wife died was the preservation of his reputation as opposed to, say, protecting his children. If Hughes really was so concerned with salvaging his reputation, then he was remarkably unsuccessful, seeing as the story of him and Plath is at least as well known as anything he actually wrote, presumably because a sensationalised story about a marriage is easier to read than poetry.

In my late teens I overly empathised with Plath in the way only an American young woman who found herself studying English literature at an English university can. But it does not follow that if one is pro-Plath, one is anti-Hughes. No one can know what really goes on in a marriage other than those involved, and the amount of intrusion – to say nothing of tragedy – endured by Frieda Hughes and her late father surely merits them some understanding and tact. Plath was killed by what she described as "the owl's talons clenching and constricting my heart". Hughes spent his life "permanently / Bending so briefly at your open coffin" (The Blue Flannel Suit). Mark the anniversary of Plath's death by reading her work: the rest, to borrow a phrase that Plath, Ted and Frieda Hughes all employed for their voyeurs, is for "the peanut-crunching crowd".