I think I do get where the OP is coming from.
DM does keep my somewhat shorter tempered DDad from doing/saying things that would cause grief.
If I feel I'm about to say the wrong thing to DSIS I phone mum first.
I do a little of the same
, acting as a filter between DD2 and DH, because they are likely to annoy each other.
I think it, often does, fall to women to keep the peace.
Partly because most Mothers spend more time with their DCs than their Fathers do. Doing the school run etc. you tend to hear more of the ins and outs of their lives. You get the unfiltered instant version of the DCs day.
Mum is more likely to know all parties involved in thinks that are upsetting the DCs.
Mum also knows DHs project is due tomorrow. She therefore knows that today is not a good time for DCs and DH to share grumbles.
Especially as most men like to fix things. There isn't a practical solution to all problems.
I think more than anything this is why women do the "emotion keeper" bit, they want to stop inappropriate actions being taken when doing something isn't the answer.