The Tax Cuts and Jobs Act of 2017 repealed the shared responsibility payment, which is a penalty for not having minimum essential health coverage (and not being exempt from this requirement). But the repeal doesn’t impact 2018; it only provides relief after 2018.
A revenue ruling is the Commissioner’s “official interpretation of the interpretation of the law” and generally is binding on revenue agents and other IRS officials. Taxpayers generally may rely on published revenue rulings in determining the tax treatment of their own transactions that arise out of similar facts and circumstances.