I'm going to try and honestly comment because some of the people on this sub are cool and they deserve a real answer. The truth is that while the IRI (Islamic Revolution in Iran) is probably the most anti-Israel political faction in our country, it would be a lie to say that anyone else gives a single crap about "better relations" with Israel.
This comment from /u/nudimmud on Iran explains why in detail:
Pahlavi II was "advised"--that is, ordered--by the US to recognize Israel despite his wishes and his populace's--those of them who knew what was going on in Palestine--wishes. Later during his reign he enjoyed the services of Israeli intelligence in counter-revolutionary operations including training of SAVAK. He also brought into his service some Israeli engineers whom he almost completely secluded from the Iranian populace. His belief was that currying favor with Jews would raise leverage in the US and he was rather open about this. However, he was not committed to support of Israel against Palestinian rights. He only found it opportune due to the Zionist power configuration in the US and across the wider West.
The Iranian public were opposed to all these dealings with Israel. It became a key talking point of revolutionary agitations. Once the revolution was realized there was one thing nobody--religious people, nationalists, the secular Left--had a problem with: severing ties with Israel. PLO had also aided the armed struggle in Iran so it was all a no-brainer. Arafat became the first foreign dignitary to meet the members of the new government. Every single one of them, including those who were later ousted and persecuted, welcomed him. Oslo was a chance for Israel to make good with PLO and fix its apartheid problem. Assassination of Rabin and the rise of Likud destroyed that. Iran remained faithful to PLO objectives just as Fatah sold out throughout the 1990s and Israel kept importing East Bloc Jews.
The case of the colony called Israel on Palestinian lands represents to Iran a case of Western colonialism that has not yet been concluded. A project that is still being pursued full force. The land theft and the demographic project under Likud rule since the early 1990s, pushed more vigorously throughout the 2000s and 2010s, have made PLO objectives outdated. A two-state solution is no longer feasible. Israel has become an artificial ethno-state whose fate will determine whether the West can allow itself to imagine colonial projects in the Middle East can go through. This is antithetical to Iranian interests in its own neighborhood, before or after the revolution.