While 100% of crooks may or may not be armed with guns, is hardly material. The point I was making is that several times more (guns) are held illegally in India, and while all these illegal gun owners may not have a criminal bent, as per law they are in violation of the Arms Act and are therefore guilty of committing a crime.
When I say not all may have a criminal bent I am referring to those people who have procured illegal arms for self protection because they have tried to and failed in their attempts to get an arms license, or maybe they simply cannot afford to buy a legal gun. They however have a threat perception which drives them to break the law to be able to better protect themselves/ their families/ their property. Since no accurate statistics are available for the illegal gun market and the general extrapolations are based on yearly seizures, I can only postulate that such people would be in the minority (amongst illegal gun owners) - but such people do exist.
Coming back to the discussion of criminals being armed. As I had mentioned earlier, criminals have the benefit of being able to plan their attacks and therefore even if they are not armed with guns and merely use knives, sticks or even fists they can plan an ambush and easily overpower their victim with greater force - with or without the use of firearms.
A case in point is the development of the Russian mafia. In it's early days of existence the Russian mafia was hindered by the strict anti-gun laws put in place by the communist administration. So they used plain old muscle power to intimidate, and in many cases even kill adversaries - yes, they would simply corner and beat to death their victims... not a pleasant way to die!

The point is, freer gun laws help law abiding citizens a hell of a lot more than criminals... in fact they have an adverse impact on criminals as the intended victims suddenly cease to be soft & easy targets! Criminals are in crime as they desire "easy money", once the money ceases to be "easy" the incentive is automatically lowered. Not to say that crime will disappear overnight, that would be a foolish assumption, but that the crime rate will begin to steadily decline.
Furthermore, elaborating on my initial point (a few posts back) on the issue being "freedom". Human beings are social animals and to live within a society we impose rules to ensure that people can co-exist with each other with minimal friction. Some rules are written (laws) and some unwritten (etiquette) - all members of society are expected to adhere to these. But each new rule we put in place, decreases our individual freedom, so we must be careful about what rules we do put in place. Debating in detail each and every proposed rule to figure out whether the particular freedom we are giving up is worth the benefit society gets in return.
A good example would be the use of so called foul language. If used in certain settings it is considered boorish, however close friends frequently feel free to use such language amongst themselves in which setting it is merely considered as a way of "expressing emotion". There is a good reason why most nations have no laws curbing such speech as the loss of freedom of speech (in any manner) in return for a politer society is not considered as benefit enough when weighed against the loss of an essential freedom/ human right.
Similarly, gun control laws are put in place to curb crime. However, we have ample evidence that this is simply not working; so why give up a huge personal freedom in return for a hollow promise?
Cheers!
Abhijeet