Being a feverish commie I'm not a fan of the Taliban.
But sadly the Taliban - in reality a loose coalition of militias - are part of the Afghan population. So they've kind of got an endless supply of recruits. Killing civilians as NATO forces do all the time - in Kabul's main hospital they have a book of around 2,000 recently killed by British forces (Newsnight) - won't stop recruitment for the Taliban.
Also being allies with the Taliban (aka: the Mujahadein) to defeat socialism in the country in the 1970s and 80s was a huge mistake.
But the US and EU would rather have right wing religious nutcases in charge of a country than socialists, where women worked, were educated, held political office. The US and EU - alongside the Soviet Union of course - helped destroy that society...and have shown no sign of wanting it back. Instead they allow a thug heroin addict to run the country, pay his brother to run death squads and load up the flow of opium and heroin in which the entire political class of Afghanistan are involved.
British forces are there to "project hard power". It is a lesson to the region, like Iraq. If you fuck with our interests we will destroy your societies, your kids, your women...mess with us at your peril. Imperialism, straight up.