Sikhism will not be extinct. Some talibani "sikhs" will live somewhere, create trouble and we will face more rigorous checking on all airports.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/sikh-sikhi-sikhism/29484-sehajdhari-sikh-federation-comments-please.html
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=29484
Hopefully there will not be any support for them in general sikh polpulation.... like it happened in 1980 and nineties. When general population support was gone, the so called terrorism died.