My take on the swearing in songs is that it's just not necessary and can restrict the number of participants. Most swear words can be easily replaced. A good example is the "effing love Derby", why not just sing "D C F C". It's a catchy tune and would travel around the ground.
I'm no snowflake and can cus with the best of them, but I just think that the songs that work best are both clean & simple.
The other problem we seem to have is the speed at which the songs are sung. We start a good old "We Are Derby" & by the 2nd verse, I'm struggling to keep up. The speed then kills it. Listen to Rod Stewart singing "We Are Sailing" & you'll get the idea. The only way to keep the momentum going is to sing at a constant pace.
The other thing I find is that you just need to keep going. Even when a song dies out, it only needs a couple of you to keep singing and people will join back in at opportune moments. Don't rely on other people.
If you want an atmosphere keep it simple & keep it going.