Yes, it's 100% white privilege.
It's so very obviously white privilege, but Mumsnet skews very right wing and has very odd ideas about racism, so of course the existence of white privilege is being mocked and belittled.
There's a reason MN has a reputation for having a massive problem with racism. Endless threads about how awful Meghan Markle and other black celebs are, any thread about a black female celeb is full of goady dog whistles, endless threads about how fun golly dolls are, how blackface is fine, how black actors shouldn't play white characters. Anyone asking "was this racist" is always told no, of course not, you're being oversensitive and "playing the race card", unless it's anti-white racism, which according to MN is the only valid form of racism that exists.
Any black posters trying to discuss their experience of racism get mocked and trolled and have their experiences belittled, and often subject to mass false reports to try to get their posts deleted and banned.
Look at the abuse when someone advocated for a Black Mumsnetter forum, some Mumsnetters were so furious they even photoshopped fake DMs to try to get her banned. Just because they were so obsessed with hating black women.
Compare the response to the BLM protests (lots of threads full of comments baying for their blood calling them thugs) vs the threads about the white supremacy protest that followed (nearly all "I don't agree with them but I will defend to the death their right to protest because of free speech).
The threads about George Floyd and Ahmaud Arbery were horrendous.
And yet being Asian allowed the rape gangs in Rotherham and elsewhere get away with their crimes because the authorities thought they might be seen as racist. I think believing LL wasn't investigated sooner because she was white is quite a reach.
The majority of grooming gangs in the UK are white, the vast majority of pedophiles and sex traffickers in the UK are white, yet they receive almost no media coverage, because they can't be used to stoke racism. The fact Rotherham has received such vastly disproportionate media coverage compared to white grooming gangs disproves your point.
There's a ton of evidence showing that people of colour are more likely to be stopped by police, searched without any reason, more likely to be arrested and charged over minor crimes, and receive harsher jail terms for the same crimes. Black kids are perceived as much older than white kids and more likely to be stopped, arrested for things white kids wouldn't be arrested for.
Threads about racism always end badly on MN because there are a lot of posters on Mumsnet who quite frankly and full on white supremacists, refuse point blank to believe that racism exists (except for "anti white racism), and seem desperate to undermine anyone black discussing their experience of racism.
The fact there are now Lucy Letby Truthers is proof of how much racism played a role. Because often when a white person is accused of a serious crime like these, elements on the far right adopt them as a cause. It's exactly the same as Sandy Hook Truthers. That would never, ever happen in a case of a non-white person committing those same crimes.