Unfortunately there are still girls as young as 13 being married off in the US against their wishes in 2017 so while it's true that developing nations have work to do , so does the US!!
Check this out

My opinion is that it takes generations to change such cultures and practices. The environment must change too so that the people can see that the old cultures and practices are actually detrimental to their happiness and existence. I think that they would change more willingly in such circumstances.

The evil of religion and culture raising it's head. It is a shame that these things that seem so natural to many cultures continue when they know the results can cause such pain to those who survive. In this case it is poison but it could just as well be drugs,cigarettes, alcohol,dieting to excess and other practices that are common in the society but harmful. It could be the practice of religion or culture that results in death. American Indians of some tribes used the right of passage for boys to place them in danger to become a man. It was not a very good custom but to them it served a purpose and was accepted.

Marriages should never be forced. All these sick men who brainwashed from generations of sick men should be killed..get rid of their DNA...so their sickness dies with them...

If the bridal killings keep happening on a regular basis, then perhaps a darwinian effect will eventually take place and that particular cultural tradition will die out (pun intended). Although as a previous comment has noted, that the odds are that it has the same effect as shootings have on changing gun laws. Whichever way, it is a tragedy for all concerned, not least the groom's family, when it was the bride's family who were the ones to betray her.

Well, you do have to address why they're being forced into marrying someone they don't want to marry. Marriage may be a way of payment of a debt, reinforcing a family's fortune, political, whatever. It's their culture. Apparently, divorce is out of the question. These are probably also very poor people who lack education. So education is the first place to start. I've met many Pakistani's. They're good people and deserve to live just like anyone else.

There is no way to influence them other than what is happening. The good news is that Pakistani's are dying so I don't care.

A tragedy caused by a malevotent tradition.

It's just another flavor of messed up thinking that's been ingrained into the heads of people to the point of them believing it's 'normal' behavior.

Something like this will probably do as much to reduce the number of bridal poisonings as the Vegas shootings did to change gun laws.

It has been shown time and again that it does not work out very well when one tries to force their values onto another. However, I do think that taking steps to help/encourage such societies to evolve on these issues should be taken. Promoting education of everyone is certainly a critical step; but, alas, in the US we have been slacking on the education front. And, look where we are now...instead of progressing we are regressing.

these people need science

Education is a good start. Eventually they get that killing 'everyone' is more from a Black Adder skit than for real life.