They have pretty damned good reasons to be upset. Even I have sympathy for them.
The problem with that logic is everybody has pretty damned good reasons to be upset. If you have sympathy for Muslim terrorists then surely you sympathize with people who commit hate crimes against Muslims. After all, think of their world-view, wherein for their whole lives they've seen acts of terrorism against their countries in the name of the Muslim religion.
What exactly do you think a 15-25 year old from Afghanistan has for a world view.
The 15-25 year old Muslims living in 3rd world countries like you're talking about don't have the means or motivation to attack the West. Many of these 3rd world terrorists are bought and paid for as young children and brainwashed to be used as weapons. If you want to read something heart wrenching, look into the stories of the Mumbai attackers from a few years ago. These guys, who genuinely deserve pity (though they still need to be put down.. they are thoroughly broken and cannot be fixed), are not well liked by Muslims unless they carry out their attacks on non-Muslim targets (e.g. India, Kashmir, Southern Nigeria, etc). There is very little support among Muslims for terrorists attacking other Muslims. They are not at all the same as the terrorists in the polls I mentioned, which were about Muslim terrorists attacking the West. I guess you have not heard about these polls.
The Western Muslim terrorists are pretty much the opposite of what you appear to think. They are often university students or graduates. They often have engineering degrees. They often come from wealth and well-connected families.
Do you honestly have sympathy/empathy for, say, Umar Farouk Abdulmutallab (the Underwear Bomber), who was the son of the "former Chairman of First Bank of Nigeria and former Nigerian Federal Commissioner for Economic Development" described as "one of the richest men in Africa" ? What is it about his situation that evokes sympathy in you?
Or more to the point of the article, look at the Tsarnaev brothers. They came here as refugees and were welcomed, given a new life. The younger brother was a student in a US university. He was a citizen. The older brother married an American girl who converted to Islam on his behalf.
I mean... you must be insane to think these guys were somehow forced into terrorism by the unfairness of the world. They were given opportunities on a silver platter. Even their own uncle called them losers and said they brought shame to their family and community. But YOU have sympathy for them? Why?