The crucial question is whether it wasn't implemented because Iran was unwilling or because China promised more than it was willing to provide after US pressure. Most Chinese probably believe most of the blame is on the Iranian side. If you can understand that, you should also understand that most Iranians are going to put the majority of the blame on the Chinese side. The truth is difficult to know without inside information
As I said before, I'm merely trying to explain why public opinion of China in Iran is not very good. It's because of how politics has played out, not racism, as certain people are claiming. I'm not arguing that China should take any risks for the sake of Iran. I'm explaining that the lack of help when you're supposed to be on the same side leads to even worse disappointment. A bit similar to how Hezbollah probably feels about Iran today. They were supposed to be on the same side, but did very little to help them in the end. This is why Hezbollah isn't active in the current war. And that's also why Iran is unlikely to help China if the US attacks in Taiwan tomorrow. If the Chinese leadership has concluded that arming Iran isn't worth it, then so be it. But you'd have to be mad to think Iranians are happy about it