Religious belief is not a choice
Religious belief is not a choice in that we cannot choose to believe a statement as the result of a conscious decision to belief or by the exercise of free will. This position is known as doxastic involuntarism.  Since belief is not a choice but explainable by natural processes, the "sin" of not believing in God is actually directly attributable to God, rather than the disbeliever. God is said to punish unbelief. However, to punish a disbeliever because of something over which they had no choice is very unjust. This raises the problem of Hell. If belief is not a choice, this also undermines arguments like Pascal's Wager which depend on belief being a choice.
- "we can see that personal secularity is primarily the result of brain function combined with access to knowledge, information, and a social setting allowing disbelief. Given the right conditions, the result will be an individual who does not accept supernatural explanations. [...] Thus, while sexual orientation is not a matter of choice, we should realize that neither are one's sincerely held beliefs about divinities. "
""Freedom of belief" (in anything but the legal sense) is a myth. We will see that we are no more free to believe whatever we want about God than we free to adopt unjustified beliefs about science or history, or free to mean whatever we want when using worlds like "poison" or "north" or "zero"."
"But at least learn your inability to believe, since reason brings you to this, and yet you cannot believe."
The contrary view is that belief is a choice:
- "If the Bible is true, then my friend has chosen an unpleasant eternal destiny."
Argument that belief is a choice
The position that belief a choice or matter or will is known as doxastic voluntarism. 
How do you decide whether to believe something you hear? You must decide whether the person who told you is credible, for one thing. Do you have confidence in them and are they a reliable source for the information they gave you? In addition to considering the source, you also evaluate what they said. Is the information itself believable? Is it compatible with what you already believe to be true, or does it violate what you think?
The point is this: You decide what you will believe. When someone says, “I don’t believe that,” they have chosen not to accept what they heard because it did not pass their credibility tests. 
- If you encounter an statement, you may evaluate it.
- That evaluation occurs by considering various criteria, such as credibility of the source and past experiences.
- The evaluation occurs in the mind.
- Therefore, belief is a conscious decision.
This argument is flawed because it treats evaluation of a statement as an entirely rational process that is performed by the conscious mind. The claim that all mental process are conscious mental process is a hasty generalization. In fact, most or all beliefs originate in the unconscious mind as part of automatic fast processes. If we see a familiar object, we recognise it quickly, with hardly any effort and without any conscious decision. You cannot choose not to recognise a common object. The belief "there is an object on the table" is therefore not a "decision" in the normal sense because there is no conscious thought required; we just believe it without effort. We cannot choose to not believe it, if we can still seeing the object on the table. Therefore, at least some beliefs are not a choice. Also, the above argument, which neglects this major mechanism for belief formation is committing a non sequitur: just because a process occurs in the mind does not make that process a decision!
"The initial attempt to believe is an automatic operation of System 1 [automatic, fast mental processes], which involves the construction of the best possible interpretation of the situation."
- — Daniel Kahneman 
If automatic, unconscious processes (sometimes referred to as "System 1" in dual process theory ) do not find the idea acceptable, it requires significant time and effort to form a positive belief using rational thought. Very often, the concept is not considered consciously at all. For this reason, belief is not necessarily a "choice" or "decision" of the conscious mind.
Motivated by theological concerns
This argument is motivated by the need to make God's punishment of disbelief justified in the mind of believers. If God punishes people for something that would happen deterministically, this would make God seem rather cruel and raise the problem of Hell. To avoid this conclusion, theists insist belief in God is a choice. This view is not motivated or supported by evidence. (This point is an observation and not an argument per se.)
An alternative view: Intellectual dishonesty allows for beliefs to be chosen
When making no attempt to be intellectually honest, however, there may be ways to influence your own beliefs. Starting from being politically undecided for instance, one could choose to immerse oneself entirely with the arguments and rhetoric of one side or the other. While the resulting belief is not a guaranteed outcome, it would certainly be influenced by choice.
This argument would make for a very poor defense of the justice of punishing on the basis of beliefs. Punishing people for their honesty is possibly worse than punishing them for something they didn't choose. However, this argument is relevant to the final step of Pascal's Wager, namely, deciding what could be done if a skeptic wanted to believe.
Belief is unconscious, disbelief is conscious
Some studies suggest that belief is an unconscious processes, in contrast to disbelief which requires concious consideration which can override the unconscious believing processes. Based on this, skepticism more cognitively taxing than belief.
"The data suggest that readers must expend strategic effort to reject the information they acquire from literary narratives."
- — Richard Gerrig 
"Analytic processing inhibits these intuitions, which in turn discourages religious belief"
- — Ara Norenzayan 
Even if disbelief requires conscious consideration, it does not necessarily make it a choice. Our conscious thinking is guided by criteria that are selected unconsciously. If one accuses lack of religious belief in supernatural deities of being a "choice", cast some light on the situation by stating a very probable interpretation, that since many theists do not believe that the physical universe is all that exists despite there being little to no documented records or traces of a spiritual realm, their belief in the existence of a deity behind everything can be summed up as "disbelief in what naturally appears to all."