Resistance of occupation, including violent resistance, is not a crime under international law.

War crimes conducted for the "violent resistance" does come under international law. There are rules of engagement all parties need to adhere to.

The State of Israel spent so long fighting monsters that it became one.

The State of Israel literally created the main “monster” it claims to be fighting (Hamas), abd did so for the specific purpose of splitting Palestinian opposition and having a less sympathetic enemy to weaken international criticism of its campaign to cleanse Palestine of Palestinians, which has been fairly overt policy since the occupation began.

That's a rather bold claim.

For instance: Both Israeli Security Minister Itamar Ben-Gvir and Finance Minister Bezalel Smotrich have been sanctioned by the UK, Norway, Canada, New Zealand and Australia for “repeated incitements of violence against Palestinian civilians."

And yet all of these countries also condemn Hamas and their atrocities....

They... don’t. The ICC sought warrants for both Israeli and Palestinian leaders (at least one of the Palestinian leaders was subsequently killed by Israel, rendering any charges moot, but the ICC wasn't ignoring the alleged crimes.)

Similarly, many countries have sanctioned both Hamas (and/or other groups like PIJ, etc.) and/or individual Palestinians for acts against Israeli civilians as well as Israel and/or Israeli politicians for acts against Palestinian civilians.