Dowry (where the parents of the bride pay the parents of the groom), in India has a minimum sentence of 5 years even for non aggressive and non-coerced dowry. This is in comparison to other violent forms of extortion, which don't have a minimum punishment. Why is that?
Dowry, in India, is a deeply cultural thing. The general gist of dowry is that the bride's family must provide sufficient dowry to the groom's parents. The problem is that it is also associated with a form of domestic violence called bride burning
"The husband's family believes they have not received enough money for their son at the time of the wedding, perhaps because they are of a higher caste or some such reason, and that's when the harassment starts."
Often, says Fernandes, the husband's family begin pressuring the wife's family right after the wedding.
"They start asking for cash, or gold, or consumer goods like washing machines or televisions. Whatever it is they believe is owed to them or was promised to them, luxury goods that they can get the bride's family to pay for."
The woman's mother-in-law is usually the perpetrator. She douses the woman with a flammable liquid and sets her on fire. This crime, as extreme as it sounds, is shockingly common in India
Bride-burning, as this type of crime is most commonly referred to, accounts for the death of at least one woman every hour in India, more than 8000 women a year.
It is a crime that has little prosecution (2015 numbers)
Of the 671 bride burnings she knew of in the area surrounding Bangalore last year, only about 50 cases had been formally registered by police last year. Nationally, convictions are secured in only about 15 per cent of cases that make it to court.
As a result, the punishments for any dowry offenses are likely higher as a deterrent to the underlying problem of bride burning.
They are the same crime in a sense but of two different kinds - one that is a crime in the eyes of law as well as in the eyes of society; another that is a crime in the eyes of law but not the society.
Someone who commits a crime of first kind has repercussions in the form of punishment prescribed by the law as well as losing societal support forever.
Someone who commits a crime of the second kind doesn't lose societal support. Hence, to compensate (i.e. so that the sum total of negative consequences of commiting the crime stays the same), the punishment prescribed by the law is increased.
There are always two punishments for an action that is seen as a crime:
- The first comes from the law court and is served in the jail.
- The second comes from the society, commonly through the loss of the social status but depending on the times one can also get hand severed.
These two systems are often approximately aligned, but there may be behavior that is unacceptable by one and tolerable, even honorable in extreme cases, by another. Some historical rudiments may still have traces in the society and be just horrible. We can hardly trace why they existed starting from, may have something to do with the life being much harder at that time.
From Wikipedia and other answers looks like the dowry related killings have low reporting, disclosure and conviction percentages. In general it is unclear what the groom, father of the bride and brothers of the bride are doing, why do not they come at least for revenge. This may indicate that the society for some reasons is somewhat more tolerant.
When the systems are not aligned, the side that sees the behavior as unacceptable, and seeks to exterminate it, may put much harsher punishment, to compensate the lack of support from another side. Both government and society can do this.