There are plenty of good arguments against SMRs: none of them include terrorism.
The theory was always that you could get economies of scale if you were building the same reactor every time in a factory and transporting it to install somewhere else. In practice those economies never materialized (did they even exist?)
Meanwhile solar, wind, and batteries have plummeted in cost. There is no need for base load power generation if we have sufficient battery storage and an oversupply of generators - which is entirely feasible for wind and solar.