They certainly did heavily target military bases with a >33% military casualty rate.
As with any armed resistance you get some people that are less educated and more vengeful. Locking people in a concentration camp for 20 years doesn’t do wonders for their mental.
Also it’s working out pretty well for them because as the popular saying goes: The guerilla wins if it does not lose. And Hamas is not losing right now.
People seem to heavily underestimate how bad the living conditions in Gaza were. There was less bombing 1 year ago but they were certainly still dying from diseases and were malnourished.