because everyone sane person knew that the Iranians could not be trusted. He nonetheless gave them cash in a deal that he KNEW had to be undone in pursuit of his foreign policy legacy.

Iran's recent missile attack aimed at Diego Garcia using tech they just promised that they didn't have a week prior was evidence that they would lie and have been lying about their capabilities as they proceed toward their goal of becoming a nuclear power. And Iran has stated clearly in action and in deed what they would do if they obtain that power.

JCPOA was always their best avenue to obtaining nuclear capability back when they had been beaten down financially and technologically for their terrorist actions.
It relied on gullibility, appeasement, and Obama's Islamocentric worldview (perhaps the reason for his gullibility).

A "whataboutism" requires one side to justify a mistake by pointing to a mistake made by the other side. But conservatives made no mistake here. The Iranian mess is all your doing. All of it.

Removing the Iranian nuclear threat was essential.