Iran appeared to be adhering to the JCPOA. In 2018, Trump in a tantrum, because Obama had negotiated it, essentially withdrew from the JCPOA. Iran, therefore was not in violation of the agreement in continuing to develop their nukes. By all accounts, they were still a long way off. Plus, Trump allegedly, according to his own words, had already destroyed their nuclear programme in the earlier bombing, which went largely unanswered for by Iran.
So, which is it? Oh, right, doesn't matter to the Trump defenders.