Not really, what he said before was true. The Dickwaving was impractical and silly, it didn't really "frighten" anyone.
To unabashedly steal from Wikipedia as to the reason bombs shrunk:
The Tsar Bomba was the culmination of a series of high-yield thermonuclear weapons designed by the Soviet Union and the United States during the 1950s (examples include the Mark-17 and B41). Such bombs were designed because:
The nuclear bombs of the day were large and heavy, regardless of yield, and could only be delivered by strategic bombers. Hence yield was subject to dramatic economies of scale;
It was feared that many bombers would fail to reach their targets because their size and low speed made detection and interception easy. Hence maximizing the firepower carried by any single bomber was considered vital;
Before satellite intelligence each side lacked precise knowledge of the location of the other's military and industrial facilities;
A bomb dropped without benefit of advanced inertial navigation systems could easily miss its intended target. Parachute retardation would only worsen the bomb's accuracy.
Thus certain bombs were designed to destroy an entire large city even if dropped five to ten kilometers from its center. This objective meant that yield and effectiveness were positively correlated, at least up to a point. However, the advent of ICBMs accurate to 500 meters or better made such a design philosophically obsolete. Subsequent nuclear weapon design in the 1960s and 1970s focused primarily on increased accuracy, miniaturization, and safety. The standard practice for many years has been to employ multiple smaller warheads (MIRVs) to "carpet" an area, resulting in greater ground damage.