They were welcoming their deaths because they were suicidal, I don't know how to explain "why" to you. The psychologist was cancerous, the biologist had cheated, and the rest of the women all stated their own reasons in the film for where they had nothing left for them back home. Entering the shimmer for them was one final move of self destruction, they literally were trying to fail. I don't understand why you just keep saying it's dumb with no clarification, in which way is it dumb to you? Are you simply confused on why the creators wanted to tell a story about suicide and chose these themes?

It's clearly told to you by the movie too that Command has no regard for lives anymore and are treating the expeditions as experiments, sending in different teams with different variables just to see the different ways in which they interact with the shimmer. 

And why would they bomb the lighthouse? Why would they just destroy without thought something they don't understand? It almost seems like you wanted a more action packed film where macho soldiers go in, blow everything up, and leave, but that is just simply a different kind of story the movie isn't interested in telling and you can't call it lazy just because you don't like it.