You are not missing anything, i feel sorry for you and your friends that you experienced something like that. DC is not a dangerous city per se but it s not a safe place neither. In some neighborhoods you might feel a little more safe than other, but always remains vigilant of your surroundings… I personally carry a pepper spray with me just in case of, even if i am not quite sure that it would help depends on the situation I might encounter. There is a lot of people in DC, who are mentally instable, you guys might have met one that day or maybe not, but do not expect someone would have jump in the middle of what s going on and took your defense… that s not something that people do in DC, the last person that did that, a couple of days ago was a metro employee who ended up dead at the end. You might have a vision of USA a little bit too romantic, and you just got a reality check that DC, the US and Americans we are not better than any other human beings nor any other country, we might often quite be the opposite. All in all my dear OP, do not let this incident deters you from enjoying your life. Once, you will pass the trauma stage, just go do your regular thing, all the things you like to do, even coming to DC again. As for taking metro, a couple of advice:

• do not isolate yourself from the people on the platform, nor riding a car with just few people
• always board the first car, the one where the driver is
• avoid eye contact with people and especially with the mentally instables.
• do not make yourself a target by wearing fancy clothes and other things. Stay really sober
• put your headphone on your ears but in low volume cause you need to hear what s going on around you… kinda « i am in my bubble but i pay attention to my surroundings »
• report any incident that will happen to you to a metro station manager at their booth or metro police… not quite sure it will help but…
• buy a pepper spray if it helps you to feel safe.

Stay safe! 🫶🏼