So in essence, CNN can't believe that the massacre is that severe?

Later in the article it talks about the horror part:

A World Health Organization spokesperson said on Tuesday some Gaza doctors had been performing operations without anesthesia, including amputations.

“Nothing justifies the horror being endured by civilians in Gaza,” WHO spokesperson Christian Lindmeier said during a press briefing. He reiterated the UN’s calls for “unhindered, safe and secure access” for some 500 trucks of aid a day — not only across the border but also “all the way through to the patients in the hospitals.”
...

Emily Callahan, a nurse activity manager for the non-profit Doctors Without Borders, was in Gaza last week and saw the devastation firsthand.

“There were children with just massive burns down their faces, down their necks, all over their limbs, and because the hospitals are so overwhelmed, they are being discharged immediately after,” she told CNN on Tuesday. “And they are being discharged to these camps with no access to running water … They are given two hours of water every 12 hours.”

She described seeing children walking around with severe wounds and “partial amputations.” Their parents would go to her and the other aid workers asking for help – “and we have no supplies,” she said.

It's a pure massacre

In case it wasn't clear, UNICEF is generally considered to be a reliable and trustworthy organization.

I wonder why they killed reporters and don't want anyone there

Old enough to remember how Biden was trying to play down the scale of the genocide his administration is funding, and to cast shade on the numbers coming out.