In short: Two wrongs do not make a right.
It is also worth noting that you are not portraying the matter fairly. You are transposing certain radical elements, i.e. those who actively defend Hamas, on to people who simply oppose the ethnic cleansing and genocide being perpetrated by Israel. I don't support Hamas, and I also don't support Israel.
Furthermore, you falsely assume that people are generally ignoring the evil actions perpetrated by Hamas, which is not the case. It is a false dichotomy to present the issue as supporting either Israel or Hamas. Hamas undeniably has engaged in terrorism, but that has no bearing on whether or not Israel is acting properly in response. The fact of the matter is that Israel hasn't merely been attacking Hamas targets that happen to also have civilians present, but rather that Israel is going beyond that to willfully engage in a near-indiscriminate extermination campaign against unjustifiable targets.