The comment is not advocacy. Had all Taliban been murdered, there would be no Taliban problem today. Instead the dispute would be between the drug lords and the rest of the civilian population.
A good chunk of upper-Taliban leadership were former prisoners that were released, leading up to the peace talks of last year. (Its better that we negotiate with moderate Taliban we chose to release from prison, rather than the extremists that come from self-recruitment)
The issue is that the Taliban can continue to recruit more and more leaders from the locals. They're able to recruit in large numbers because the Afghan culture glorifies their resistance across the 1800s against Great Britain (and other world powers with superior tech).
Their entire culture is optimized about fighting against foreigners and rallying locals. The more we kill them, the more they're able to recruit.
Afghanis stopped doing that for the period the Mongols ruled via one demonstration of regional depopulation through municipal-scale genocide [1]. But the Mongols were like that: they were quite progressive and often ran on a benevolent dictator model, but you cross them just once and they salted the earth after they were done wholesale killing everyone, innocents included.
But the Mongols' record in Afghanistan was likely only possible because they established a reputation for carrying out these genocides on various scales (Khwarazmian Empire being a notably bloody example). I suspect China comes closest in the current era to that level of determination; fortunately for Afghanis, China is not demonstrably interested in Afghanistan.
[1] https://en.wikipedia.org/wiki/Invasions_of_Afghanistan#Mongo...
[2] https://asia.nikkei.com/Opinion/The-myth-of-Chinese-investme...
Never underestimate the horrific wartime capacity our species are capable of unleashing. In the sweep of recorded human history, we happen to live in an era of relative peace, and even most of our worst wars today play by Queensbury Rules compared to the relative scope, scale and ruthlessness our distant ancestors regularly abided by. To give a sense of proportion, Genghis Khan is estimated to have killed 11% of the world population; scaled to today it is 0.84 BILLION. He would have literally erased the entire male population of Afghanistan and hardly noticed by his standards. None of today's relative decrease in bloodthirstiness is enshrined like laws of physics, and is but a thin veneer upon our civilization when push comes to shove.
Should climate change worst-case scenario predictions come to pass, desperation can erase that tenuous progress in decreasing human misery, relative as it is, in the blink of an eye. It is best we all remember that War Is A Racket, and anytime two or more sets of elites clamor for war, we'd all likely be better off they were all the first killed on the front lines, and then we all re-evaluate the "need" for war again with a new elite who want to go to the front lines.
We departed from U.N. Charter article 51 twice, and also disregarded the determination of Nuremberg. The nation is complicit, Bush was reelected subsequent to his foreign policy assertions and actions. There's been no serious consideration to hold him or the U.S. accountable. That makes it tacitly permitted.
Killing all Taliban would not be genocide. It would be consistent with long standing U.S. foreign policy. It's a religious sect, not a group of ethnic or nationals.