I believe Americans arbitrated between both sides. US was at that reliant on Pakistan and the Afghan jihad. The last thing USA needed was their two allies start hurting each other. They told Israel lay off and got a promise to Pakistan that nukes would be Indian centric. And that understanding has stood for all these decades. All Pak nukes are firmly pointed east.Since it was not an attack directly targeting Israelis and Pakistan is a rather militarily powerful country that Israel would likely rather not annoy, they probably let it slide.
1.4 billion Indians erased. US sheds a crocodile tear. 5 million Israel wiped out. America would go berserk and actually visit on Pakistan what it threatened in 2001 that caused Musharaf's legs turn into wobbling jelly "bomb you to stone age".