This is not true you can just google Qassam brigade to see their uniform, they have a very emblematic headband. They are hiding in tunnels though so you're not just gonna find them everywhere, Hamas does not have military equipment to be able to fight head to head with a modern military, it's just an insurgent group.
> once something is used for military operations, it is fair game as a military target.
Except you have to prove it was used for military operations, not just bomb hospitals. This is called a war crime.
> Regardless of civilians
well well
Also, Hamas's leaders are worth over $10 billion collectively. They can at least afford basic uniforms and spray paint to mark their vehicles. But again, they won't do it, because civilian deaths are the last piece they have left for international support. Which comes in the form of aid, which they seize, and pad their $10 billion with.
Take the Mahmudiyah case: https://en.wikipedia.org/wiki/Mahmudiyah_rape_and_killings
Lifetime imprisonments
The difference here is that when Israel does so - which is exceedingly rare - it is merely a slap on the wrist. Weeks to months in prison. Where's the deterrence in that?
When the US was in Afghanistan, Al Qaeda learned that the US (generally) won't shoot ambulances. So what became the most valuable vehicle to Al Qaeda? Hamas took notes, but Israel doesn't seem to care as much as the US.
Also, besides all that, once something is used for military operations, it is fair game as a military target. Regardless of civilians. When the law was written it was assumed that governments wouldn't intentionally use their civilians as protection.