What is the fallacy that claims the victim is more developed just because they're the victim?

I actually added the appeal to victimhood as a form of the Appeal to Pity in the latest edition. I will update the webpage now:

The appeal to victimhood uses a form of pity to either establish the innocence of the victim or suggest the victim has the truth on their side. This is an application of the halo effect, where victims tend to be seen positively, therefore that which is associated with the victim (e.g., their innocence, or their claims) is also seen as positive (unreasonably and without evidence).

Before anything else, the parties need to define their terms.  For example, what does "progressive" mean?

The argument is very weak, since none of the reasons offered in support of the conclusion are very relevant. The fact that a country is the "victim" in a conflict only means that, and says nothing about how advanced it is - technologically or otherwise (that's a Non Sequitur). The premise is also tangential to the discussion - victimhood is an emotionally-loaded concept that is often used to elicit sympathy and thus, sway a judgement (that's an Appeal to Pity). 

Nominal fallacies are non sequitur and halo effect as suggested in other answers. But there is another problem. 

Pakistan wages total war on Bangladesh and attacks a non-combatant population. Total war takes the enemy as a whole, where civilians are a supportive part of the enemy's organized effort. There is a red line between total war and genocide or democide. I will assume Pakistan was "only" warring to keep this answer short.

On the other side of the conflict, Bangladesh wants independence. Once again, there can be several justifications for a claim of independence ranging from patriotism to nationalism, and to violation of certain universal principles. I will assume the Bangladeshi were patriots to keep it simple. 

The Bangladeshi has less resources to fight. The Pakistani wants to overwhelm the enemy. The weaker side of the war is glorified for being weak. On one hand, it is a propaganda stunt, hence logic does not apply. On the other hand, it is nihilism, hence logic does not apply. The latter case, however, is a political weapon in widespread use.

A claim of moral superiority because of being weak, being poor, being incapable is a fundamental rejection of all values. If the Bangladeshi will be morally superior because of being weaker, anyone weaker than the Bangladeshi will be morally superior to the Bangladeshi. It leads to the ultimate weakness of not being. Not to be will be the highest value, which is a contradiction in terms. The same debate can be found in St. Augustine's description of City of Rome and Jean Jacques Rousseau's noble savage. The Comanche will be morally superior to the Europeans because of being less advanced. 

It is Oriental thinking weaponized for politics. Recently we see it in political activism. How to handle it can be important.

When weaponized, nihilism must use equivocation . Being weak as morally superior labels weakness as value. If a nihilist debates for all men as created equal, he must assign a positive to the Bangladeshi, and everybody else, in which case he loses his weapon and disappoints his boss. To avoid that, he equivocates a negative (weak) with a positive (be).  

To disable the equivocation, one should assert the positive for the entire class of the beings or the things in discussion: All men are created equal. All individuals have the same rights regardless their ethnicity, gender, etc. All wars are bad. 

As this argument deals specifically with Bangladesh (formerly East Pakistan) and Pakistan, the claim that Bangladesh is the more developed, or progressive of the two is largely situational. It is not illogical for a modern Bangladeshi to claim superiority over Pakistan to another Bangladeshi because the nation was created by the uprising of the Bengalese majority. 

In turn, it would be perfectly plausible to argue that Pakistan is the more progressive because it was originally formed as an amalgam of diverse tribal communities, e.g. the name Pakistan itself implies a unified nation comprised of the four dominant peoples of Northern India: Pashtun, Afghan, Kashmiri, Indian, (and many others). PAKI- stan.

Now, we have to more clearly define what is meant by the word developed, and does this necessarily translate as progressive? Is this false equivalency? For instance, a previously colonized country (victim) might be more socially and politically developed than the country that occupied them, but woefully disadvantaged technologically or infrastructurally. (Native American)

It becomes more of an ad misericordia fallacy when claiming that victimization as a whole inevitably leads to superior development. Sadly, there are just too many examples where this is decidedly untrue.