What does it mean to be black? The debate around racial identity has been reignited after Anthony Lennon, a white British theatre director, was awarded a job aimed at increasing black representation. What makes this story particularly controversial is that Lennon, despite having two white parents, has in his past been mistaken for a mixed-race person and once described himself as “African born-again”.

Lennon, a former actor, was named as one of four “theatre practitioners of colour” to benefit from a £406,500 two-year funding package from Arts Council England. The programme is designed to help ethnic-minority theatre practitioners establish themselves in an industry that has failed to attract a diverse workforce. But should he be treated as black, and therefore be entitled to benefit from such diversity schemes?

The notion of racial fluidity, or transracialism, first hit the headlines when Rachel Dolezal, the white woman posing as an African American, was exposed in 2015 and used it in her defence. The terms apply to any person identifying with a race or ethnic group that differs from their biological reality or heritage. Being transracial is not the same as simply “feeling” black, or Asian, or white. It is the complex situation of being split between cultures and denied knowledge of one’s heritage.

Lennon has been identifying as a mixed-black man for large portion of his life, both on and off stage, and some believe he has a legitimate claim to blackness. Unlike Dolezal, Lennon hasn’t had to alter his appearance to be seen as black, stating in 2012 that he went through “the struggles of a black man, a black actor” when it came to landing roles. In 1990, he starred in a BBC docu-drama about his experiences and the show’s publicity declared that Lennon’s parents “both come from Ireland and are both indisputably white”.

I know that racial fluidity can be a very real, very unsettling experience, but I’m not convinced that Lennon’s story relates to this concept. I was born to white parents, one of whom is Irish, with no real explanation for my obvious blackness. I looked mixed race, but found that well-meaning whiteness scrubbed out a large part of who I was. We didn’t discuss race within my family, and anxieties around whether I was really related to my parents disrupted an otherwise happy childhood, until a DNA test later proved my mother had an affair. Since writing about this, many others have shared with me strikingly similar battles of belonging: black adoptees who have been raised in white spaces; those who have been lied to about their heritage; others who have had their identities rocked to the core with DNA test revelations.

We don’t know whether difficult truths about Lennon have yet to emerge. The black-Irish “throwback gene” story that some say applies to him was also repeated to me to justify my family narrative. Lennon hasn’t spoken about any genetic evidence of his heritage, so who knows if there’s something he doesn’t know, as there was for me. I can relate to his description of flirting with multiple identities – and in psychological terms, there has been much written about how the ways others view you can contribute to your overall sense of self.

However, I’m concerned that the conversation around racial fluidity continues to be hijacked by a privileged minority, white or white-passing people opting for a performative, monolithic type of blackness that fails to acknowledge the complexities of being a real-life person of colour.

Lennon’s new racial identity was apparently born after he failed to achieve success in the acting world as a white man. But this means he may have prevented talented ethnic-minority actors from accessing an already very limited pool of funding in the creative industries. One therefore can’t help but compare this maddeningly entitled approach to Dolezal who, as a white woman, unsuccessfully tried to sue Howard University in 2002 for discriminating against her because of her race, before deciding that co-opting blackness would improve her career chances.

But those of us who have been denied knowledge of our true cultural identities, and who cannot shed our obvious blackness, are often barred access into white society. As I well know, a white upbringing does not excuse you from the pronounced experiences of racism beyond the home, nor does it automatically equip you with the language and confidence to smoothly navigate multi-racial spaces. Often, we can feel adrift between several worlds: unable to moor ourselves to one culture, rejected from another.

Minorities who have been raised within white spaces are constantly reminded of their “otherness”, no matter how light their skin, or their parentage. This is because whiteness is an impenetrable and wholly exclusive construct which relies on the myth of racial purity to position itself above blackness. If Lennon has no claim to blackness and has simply chosen to identify as such, then he has erased the identities of those who cannot choose, adding himself to a growing number of white people who cherry-pick minority identities like costumes that can be discarded at will. He has also muted a complicated dialogue for those who have been denied knowledge of their heritage and who identify as transracial.

Many black people continue to be pressured into transcending their race for socio-economic protection or due to familial and cultural expectations. Using racial fluidity as a weapon is simply a more covert, insidious attempt to silence minority progress and elevate whiteness in spaces where it does not belong.

• Georgina Lawton is a Guardian Family columnist and freelance journalist. She blogs about travel, identity and lifestyle at girlunfurled.com