MQM behavior should not be looked at without considering Karachi's political history. Remember folks, we are talking about "political" history here. And this is no way a condemnation of Urdu speaking community as a whole.
Karachi politics was traditionally dominated by two strains. One was Jamat Islami and the second was the Shina Sunni struggle that kind of came along with immigrants from their Indian homelands.
Jamat Islami had total dominance in Karachi, and JI used its terror tactics to cull the opponents from socialist parties. Year and year out, JI would win almost all Urdu speaking seats whereas the same party suffered terrible defeats in the rest of the country. Few exceptions were a seat here or a seat there in the up country.
The second and much more violent streak in Karachi politics came from part religion and part ethnicity. As I said earlier, the immigrants from India brought along serious hatred on Shia Sunni lines. There used to be violent clashes between the two sects pretty much on the same level as modern day sectarian violence in Kurram agency.
Urdu speaking community also harbored strong dislike of Pashtun bus drivers and such feelings boiled over in anti-Pashtun riots after a little girl was run over by a bus.
So this was the caldron in which MQM was conceived, given birth to, and raised as a dominant political party in the Sindh.
In fact MQM's very seed came from the violent politics in Karachi's universities and colleges.
Thus considering the background, MQM was destined to use terror to mould its future. In some cases it was deliberate, and in other cases it was merely defensive. MQM has seen many of its workers and leaders ruthlessly killed, and yes MQM has killed its opponents mafia style. In many cases it was a turf war akin to the gang wars of Los Angeles and other American cities.
Guns, drugs, and pure extortion has been used by almost every party in Karachi, and MQM is no exception.
So the intolerance in MQM must be looked at in the backdrop of Karachi's ethnic and sectarian politics, and it should not be singled out as "the violent party".
The conclusion of ur comments is, Entire city of Karachi is has violent nature.
So blamming a single group is not right thing to do.
Keeping above scenario in mind, what is future of the kids in Karachi. Are they going to grow up as killlers and violent? Is there any system which will make any change in the nature of these people? OR it is assumed that all kids have to reap what their elders are sowing?
I don't know about MQMers and other violent groups, all i know, even animals try to give their young ones a better enviornment to florish.