Again, you are misunderstanding what we are saying. Let me address each of the problems you are talking about:
1) Marching the band into a crowded area - This was wrong. It is the fault of the band's leadership as already discussed. This is not the fault of the individual members. It is not inherently dangerous to anyone to do this as long as everything else goes right, but it is a stupid idea that is going to clog up traffic. This was not a fatal error, the band could have simply just walked together as one unit without playing and moved with the crowd as it slowly filtered out and there would have been no real problems.
2) Unyielding band - There are two aspects to this. One, that the band kept marching forward and shoving people out of their way. This was wrong and again it was the fault of the leadership up front. This is what caused the real problems. The responsibility of the band leadership was to slow the band down or turn them around after seeing the crowd ahead. Two, keeping people out of their ranks. This was the correct behavior for everyone involved because it keeps the band together, keeps people from getting mixed in and possibly knocked over, gets the band out of there faster and eliminates the potential for conflict faster, etc as already discussed.
3)Swinging their Instruments - This was wrong by the individual members of the band. Band members practice these horn moves while playing certain songs to the point where it is muscle memory so I could understand them starting the movement by instinct, but with the tight space they should not have done it or stopped immediately if they accidentally started by reflex.
4)Playing of the Fight Song - This was primarily wrong by the Iowa band leadership. They are the ones who called up the song and the ones who had the ability to call a stop to it. They failed to do that and are in the wrong. This was also partly wrong by the individual band members. Again, the band practices following these commands to the point that they are muscle memory so I can understand if they instinctively started to play on the command, then stopped or toned it back. If they were obnoxiously playing in someone's ear, they should have quieted down or stopped playing. If it were me in that position, I probably would not have played because it's just a stupid idea to call up the song then.
Another point to bring up is that most of these things, taken by themselves, are really not egregious. Walking into a crowded area - fine. Playing music - fine. Walking as a tight group and not allowing people through - fine. Doing standard horn moves - fine. Put them all together and they create a problem. The Iowa band leadership should have known this, the individual members should have also realized this and done their part to minimize the "damage", but I am not going to blame the individual members as a whole unless they individually did something wrong (hit someone on purpose, didn't apologize if they hit someone by mistake, etc).