Having security at an event doesn't make it not be a primarily civilian target. It's especially ironic that hamas targeted a peace festival that was sympathetic to their cause. I imagine it's because they don't want peace

There are plenty of examples. Tel Aviv has dozens of military bases near dense residential areas and even hospitals.

These are not hospitals and elementary schools from which rockets are being launched. They are based near a hospital which eminently sensible for any military that values its soldiers.

Gaza is the 2nd - 3rd most densely populated area in the world, only 12 km in width. It is a concentration camp.

Auschwitz, a famously prolific and reasonably large camp was less than half a kilometer in width. Please don't cheapen the experience of those rounded up at gunpoint and forced into cattlecars by comparing it to that of people who moved into an area whose inhabitants were forcefully evacuated (Israel forced its own citizens out at gunpoint in 2005. If hamas had any interest in Israel continuing to give them the land they wouldn't use the land given to them to pull this kind of crap)