I think there is a serious point to be made here, which some of the previous posters have touched upon.
First of all let me say I've been a Rovers supporter since the 1970's (as soon as I was old enough for my Da to bring me to Milltown). There has always been a rivalry between Bohs and Rovers but my recollection of the games at Milltown in the 70s and 80s was that it never manifested itself in violence of any sort - and this was at a time when hooliganism was at its most vicious across the water in Ingerlund.
I don't know what has happened in the last 15 - 20 years but these days I just cannot bring myself to actually go and support my team at a game due to the intimidating atmosphere generated by a sizeable amount of Rovers' following. It's sad. I'm not the only one who feels like this - there are 4 generations of Rovers supporters (or rather, people who would like to continue to support Rovers) in my family and none of us go to the matches any more. I have many more friends who feel the same way.
For football to grow in this country, it needs to be all welcoming. Everybody who goes to a match deserves to feel safe and secure no matter what team they support. I'm sure there are many others like me who won't go to matches any more because of the scum who have hijacked the game for the sake of their own sick amusement. I think it's up to the clubs to do something about this. I can understand any concern clubs might have with regard to losing attendance money but it's my opinion that, in the long run, more people will go to the games if troublemakers are banned.