Not true. One simple reason could be just to keep the appearance of the program ongoing in order to gain leverage in negotiations. Remember that Trump pulled US out of the negotiations on his first term, this could easily just be Iran's response to it.
E: and is it acceptable when used against Israel/US?
If I point a gun at my wife during a divorce proceeding and a cop shoots me, that's on me, no? Even if I never meant to pull the trigger and the gun wasn't even loaded.
The real reason is this: Israel is in a unique position where they have removed all threats at their borders so they can finally attack their biggest enemy. So they do that, and while doing so pull the US with them. We are at the brink of a massive war that will have millions of casualties, with even more millions fleeing to Europe, destabilizing the world even further.
You probably bought the reasoning about Saddam's WMDs as well.
This thread started with you saying "maybe they are doing it as a negotiation tactic". And yet simultaneously you think it is everyone else's fault if such a tactic is taken seriously?
You can't have it both ways.
I don't know how you could read my comment and conclude that.
Sure, we can call it high stakes negotiation tactic if that's what you prefer, but let's not kid ourselves why the attacks started in reality.
Iran has produced a large amount of >60% U-235 (enriched), probably hundreds of kilograms, way more than would be required for any peaceful purpose. I don't think any modern medical uses actually require enriched uranium any more. And anyway, how much medical imaging or radiation treatment could you possibly be doing? And they could be developing propulsion systems, that wouldn't be a peaceful purpose (it would be a military ship).
Put all this together and it seems abundantly clear that the sole purpose of Iran's HEU program is the production of nuclear weapons. HEU isn't required in any significant amount for peaceful purposes.