It's true that some reject the idea of group selection, but there are lots of scientists too who embrace the idea. Lots of very good talks/interviews on YouTube with scientists & researchers on the subject.

IMO there are too many phenomena that are very difficult to explain only with individual selection, but trivial to explain with group selection.

Not sure about the claim that evolution favors groups whose rejected members die (not sure what rejected even means in this context), seems to me like that would depend a lot on environmental context and vary across species and across time.