Marvel's Black Widow

The whole world knew Rogers was Captain America and it it is clear that Red Guardian is talking the Captain America. The one Nathashia worked with.

I doubt Johansson cared about building up Pugh, if anything she likely supported it as it is the culture of most MCU films to introduce other characters - she benefited from it herself in IM2.

Understand your point regarding the risk to BW in the movie but that is the case for all prequels and it is very rare that a named hero dies in any movie. BW movie does however add to the level of new trauma when it comes to where she is mentally in Endgame and the sacrifice she makes, especially as we see in Hawkeye that

I felt very similarly, whether the comment was right or wrong from our perspective his response fit into everything else we saw about the character - he loves the girls but his hopes and dreams for them was never what we'd expect from a normal parent, he saw them having a successful happy life being one where they were spies and killers. He never thought about what that cost them from a health or emotional perspective and when confronted with it here he deflects in the cowardly way he does repeatedly during the movie when things clash against his worldview.

No one criticising the moment suggested Red Guardian get all emotional and start apologising.

He could have been silent which showed he understood or it could also have shown that this was the first he knew of it.

Or let the let the moment as it (as Foxtrol says he never thought about the affect on the children) and later in that scene with Yalena before they are grabbed he says he is sorry this thing was done to her.

The way it is makes it feel it was brought just for laughs