At least on the Israeli side, this is wrong. An enormous majority of people are convinced that the war is justified. 1200 dead; that would be the equivalent of 40,000 Americans. 240 kidnapped, with 137 still there. Hamas have proven their capabilities and determination. And then they say[1] that they intend to do it again. When someone tells you that they want you annihilated, and intend to attack you, believe them.
[1] https://www.memri.org/tv/hamas-official-ghazi-hamad-we-will-...