No-one is taking the FR24 data as 'gospel' but it does look fairly stable and give an outline indication of possible reasons. For instance the altitudes are relatively stable on both aircraft, the fixed wing appearing to take a reasonably rapid descent within the last 20-30secs. This we know because it was initially at 3000+ft and the helicopter always had been around the 1000'ft.
Best to wait and see what the accident report says and if the FR24 data is all wrong, then it's all wrong, and it shouldn't be used to 'second guess' reasons for such a tragic accident.