Reflections on yesterday's events

Yesterday, an Israeli-Arab walked into the Merkaz Harav yeshiva in Jerusalem armed with a Kalashnikov and open fired in the dining hall where around 80 people were eating lunch. 8 students, most under the age of 20, were killed and many more were injured. Once the news got out, there was a huge victory celebration in Gaza. And the twist? The terrorist was an Israeli citizen, most likely from East Jerusalem.
I'm not sure how to feel. Obviously, I'm horrified considering that this is the second attack of the year whereas last year there were no piguim. I'm a little concerned that this could be the start of the third intifada, and I've been praying that it's not and that things will get better.
I do feel a little... selfish? Spoiled? I'm not sure how to phrase it. This event has really bothered me and I've been thinking about it a lot, and it's made me really confused. But I can't say that I feel the same way about the IDF operations in Gaza last weekend. Around 70 Palestinians were killed and hundreds were injured in "the highest number of casualties recorded over such a short period of time since Operation Defensive Shield in 2002." Many of the people killed and injured were civilians, unaffiliated with the rockets being fired on Sderot and now Ashkelon.
My response to the reports in Gaza was not sadness, fear, or discouragement as it was for Jerusalem, rather I felt anger.
I think this is a significant, if not favoritist, reaction, and it bothers me. Of course, there are major differences between both attacks. The attacks in Gaza were not targeting civilians, and the yeshiva students in Jerusalem were my brothers; I have an inherent, unexplainable connection to them because of our shared ethnicity so it is understandable for me to feel a bias towards them. But I think that having that connection is troublesome. Every life is holy and valuable, whether it be Jewish or other, and my uncontrollable tendency to take sides makes me feel like an asshole. How can I feel sorry for these Israelis when less than 100 miles away Palestinians are in a constant state of fear as they try to live in conditions that are a constant violation of their human rights and dignity?
I read an article on BBC news where two women, an Israeli from Sderot and a Palestinian from Gaza City, are exchanging letters and allowing the BBC to post them on their website. Anav, the Israeli, starts by writing about how she feels like she's living in a war-zone. She talks about the terrible conditions in Sderot as she is constantly afraid of getting hit by a Kassam rocket. Mona, the Palestinian, writes back in a very stern tone, seemingly offended by Anav's words.

Is life in Sderot a war-zone?! Then what words should I use to describe Gaza?
Life in Gaza is like Hell.

Can an Israeli in Sderot really say that he or she is living in worse conditions than a Palestinian in Gaza? Obviously not. So then why do I feel compassion for the families of the 8 Israelis killed in Jerusalem, yet I have trouble mourning for the families of Gazans?