The scientists are from Nigeria, one of the largest producers of palm oil, so it could be in their nationalistic interest to dismiss palm oil health concerns to promote their international exports.

That’s a valid point, but it could be that they’re looking at the global reaction to something they’ve consumed locally for thousands of years with consternation and wanted to investigate it.

I’ll stick with doing what the mainstream tells me until and unless the mainstream changes.

That feels like it might have sounded different in your head or I’m not understanding what you mean. There have been many examples of an incredibly unhealthy thing being very mainstream (lead, more than once, but also arsenic, radium, and mercury, for some of the most egregious examples, but pharmaceutical history is also full of this), so I don’t know why you would want to default to the mainstream on this if that’s what you did mean.

whether palm olein is a better substitute for soybean oil is a separate question from whether the solid palm oil is a better substitute for butter, which the Nigerian paper just lumps all in the same category

This is also a fair criticism, and I wish there were more research.