Sure it's fine to be upset, but being upset 100% of the time means you're vulnerable to emotional manipulation and become disconnected from reality. Trump supporters also have good reason to be upset about current economic conditions, don't they? But they're upset at the wrong people because they're blasted with emotion non-stop and don't ever think about how things are.
The political leadership of Hamas are billionaires living in luxury in Qatar while their people die. The local leadership in Gaza living in underground bunkers that keep them safe while the people above them die. They use religion to justify their actions. Like all authoritarian regimes they are very good at propaganda to keep their population in line and to gain support from foreigners.
This fascist organization launched an attack on October 7, 2023 where they went into villages and murdered women and children. How upset does that make you? Apparently not that much, which is concerning. The goal of this attack was to start the war you're seeing play out now. During that attack they took hostages to force Israel into a ground campaign. Ground campaigns in a densely populated area is known by everyone to result in the highest amount of civilian casualties. Hamas knew this, it's what they wanted. Because they can use this to create effective propaganda.
The emotions you're feeling is proof of the effectiveness of Hamas's plan. They made this happen to make you sympathetic to them. And because of how effective this has been they will likely do it it again.
In a few decades time when this all happens again, you'll be saying the same things to the younger generation as I'm saying to you now. This cycle won't end until we have a generation that can see they're being manipulated. Unfortunately you're not the generation that will end the cycle of violence. Maybe Generation Z+1 will be the ones that won't fall for the propaganda. If we survive that long.