The Taliban's word is shit. They haven't kept any of their promises about treatment of women, or not harboring Al-Qaeda. The 8 years they were in power in the 90s their camps trained 20,000 fighters who went on to commit atrocities across Africa and the ME. There is every reason to think they would do it again. There might be nothing the West can do for the Afghan people, but should definitely not give them the means to expand their regime.