For many years, the "standard rule" was........never kick at a ball in one pocket.
That was the gospel according to the greats of the past...DiLiberto, Allen, Squirrel, Taylor, etc. etc.
Yet, watch Alex the Lion and "Big Tony"....they kick at will, they execute planned safeties from kicks as well as pocketing balls.
The game has evolved. And that is a good thing.
Comparing the pool players of this modern era to those of the past is similar to comparing the fighting skills of Joe Louis to Muhammed Ali. It just cannot be done in a rational way. (And no fan loved Louis more than I did.)
Emotional attachment is a wonderful and honorable trait, but it can certainly override cold analysis.
The modern one pocket players are in a class by themselves.