Why people shouldn't carry guns?

Note that this answer is for providing possible justifications for the question, not to debate whether the question is correct (i.e this is NOT a should-or-shouldn't-they question). Please provide only answers that support the question's assumption that gun carry should not be allowed. Answers supporting the opposite view should go in another question.

Also, note this is about carry of firearms, meaning the possession of guns in public. This question is NOT about general legal ownership of firearms.

Here are some reasons why carrying guns in public can be considered a bad idea:

  • Private citizens are not well-trained in their use. There are no standards for marksmanship for possession of a gun, and there certainly is no requirement for education on proper use. Having a deadly weapon usable by anyone with no required training or education seems like a very bad idea.
  • Citizens are NOT law enforcement, and not only do not have required training in the proper use of firearms, but have no experience or education in the legal aspects of firearm usage. That is, we cannot show that citizens know when they can use their guns.
  • Even those with proper training often exhibit poor judgement in the high-stress situations where firearm use is justified. Similarly, even those with a large amount of training exhibit bad marksmanship (well less than 50% of all shots fired in justified police shootings actually hit the target). Having a larger number of armed people means that in any situation, there were certainly be a much larger portion of missed shots, and those shots are highly dangerous to bystanders.
  • Due to a variety of factors, criminals are more likely to take a gun away from the citizen, than the citizen is to be able to use the gun to protect themselves. That is, by carrying, you effectively arm your attacker in many situations.
  • Not all firearms are appropriate for all situations. Unless you are a professional law enforcement officer, you can commonly face a situation where your particular choice of weapon is inappropriate. Nonetheless, possession of a firearm results in a VERY high tendency to use it, even if it is an (objectively) incorrect decision. This is a human mental issue, as in high-pressure situations, people are apt to use whatever tool they have at hand, rather than do nothing, even if action is the wrong choice.
  • Easy access to firearms leads to rapid escalation of conflicts. That is, fights escalate from mere verbal confrontation to a deadly shooting, rather than remain at a verbal (or even merely fistfight) confrontation. That is, having a gun around breeds the temptation to use it.
  • Guns lead to overconfidence, and thus, to excessive risk-taking. For example, in the majority of any time of confrontation, retreat/fleeing is the most advisable course of action. Guns reinforce aggressive tendencies, overriding the more logical "flee" impulse.
  • Guns confuse the situation for law enforcement. Having multiple people brandish firearms in a situation makes it difficult for the police to properly assess the situation, and thus, makes it far more likely that the police will fail to respond properly (e.g. shooting a nominal "good" guy, and/or letting a "bad" guy escape).
  • Gun carry can lead to vigilantism, where ordinary citizens substitute their decisions for that of law enforcement. Which leads to the undermining of our justice system.