I've found the same. The younger lads rarely cause any serious problems.
My seat is at the back of the Kop, next to Gangway E, so the group of lads in question are immediately to my left. I heard nothing amiss on Saturday, and haven't done (aside from the very occasional comment out of line) for a long time.
The basic point is right - the atmosphere from Blades fans could be a great deal better.
People have different ways of enjoying football, and the key is to prevent them getting one another's way. It's not terribly difficult, it just need a bit of basic organisation. You define certain areas of the ground as 'singing' sections, with suitable warnings that the atmosphere can be a little more raucus than other areas. It doesn't need to be a whole stand - just (e.g.) the back 20 rows of the Kop would be fine.
Similarly (and more importantly) at away games, sell the tickets as 'singing' and 'family' (or whatever - I'm sure someone can come up with better names) with the tickets at the back being the former, and the ones at the front being the latter.
That way everyone can enjoy the game the way they want to, without annoying others.
Mind you - if the lads at the back of the Kop carry on trying to get Wednesday songs going, they'll struggle to gain much support, even from me...