It is not insulting what so ever. Every single agreement that two parties enter is a temporary agreement that will be broken. The only question is when. The history is littered with the agreements/treaties between countries that were tossed.

Every single diplomat knows it, which is why diplomacy is about horse trading. Parties want to "sort of" maintain the status quo, even if it means giving up some of what is "rightfully their" by the agreement.

This argument reeks of "not my fault you were conned, you should have known I'm a conman"

Iran got their pallet of cash, they knew Obama was making the deal without the support of congress thereby giving the middle finger to US citizens. It would be diplomatic malpractice to not forecast the deal getting revoked, especially if they violated it (and they did)

How did they violate it?