I bet there is nothing funny about a fart in a spacesuit. Nothing.
Astronauts are only allowed to eat a "low residue" diet. This is to prevent the "daipers" they wear while in their space suits from filling up to fast.
Passing a wind will not damage the suit or asphyxiate the astronaut!
Aside from the odor, farts are flammable...and in a confined space like a capsule, my guess is that there is some minor concern for danger.
Would you want to be trapped in an air-tight spaceship with a guy that just had a Mucho Macho Bean Burrito???
They're not allowed to eat a lot of stuff, surprisingly! Beans just happens to be on that list... I noticed that the list is a lot of starchy foods - maybe space does something with the starches?!
Because their suits are airtight.