I'd say it's rare, but (fortunately) not that rare. There have been many great films that show men in their full emotional range while being supported by other men. https://twitter.com/radicalbytes/status/1325884146829418496

The most obvious answer (I think) would be The Lord of the Rings, which features many moments of men shedding tears in front of others. My personal favorites would be Theoden crying at the grave of his son, and Frodo and Sam on Mount Doom

The other obvious candidate is Will breaking down and being embraced by Sean in Good Will Hunting

Then there is this heartbreaking moment from Straight Outta Compton after Dr. Dre tells his friends about the death of his little brother

And a sobbing Robert Deniro being embraced by Jeremy Irons in The Mission

Warrior features a complicated father and son relation which accumulates in this moment:

Not to forget, Oskar Schindler's 'I could have done more' moment at the end of Schindler's List:

Signs also has a sad dinner scene resulting in a beautiful embrace:

Though not met with much support, there is the greatly cathartic moment where Tom Cruise lets it all out in Magnolia

Short Term 12 is also a real gem when it comes to exploring and expressing (male) vulnerability

Though not in front of other men, there's this moment from Interstellar that's definitely worth sharing:

Coming Home has a great finale with a Vietnam vet breaking down in front of a whole school:

Good old Mr. Rogers always allows other men to express their feelings:

Wind River has two men bonding of their shared grief and sorrows:

First Class has this scene with Magnet and Xavier:

Interstellar again, Matt Damon finally sees another human being after years of solitude:

Alexander mourns the imminent loss of his friend:

Speaking of Colin Farrell, there's also In Bruges:

Another moment that's not in front of other men, but Fassbender is straight up ugly crying in this one and it's beautiful:

Two former enemies reconcile in The Railway Men:

And lastly, for now, is the ending of True Detective season 1; the light's winning: