You assume that SIS, Al Shabaab, Al Qaeda don't have goals beyond killing, and I think that's incorrect. AQAP seems to mostly want Western interests out of Yemen and Saudi. Al Shabab are loosely Stalinists and seem to be looking to control territory in Somalia and Ethiopia with Islamic jurisprudence , and I think they have some land issues not dissimilar to the EZLN(though I'm not sure I understand that correctly). ISIS/DAESH seem to want to draw Western powers into a costly proxy war with the aim of toppling regional powers. As evidenced by their early successes they seem to aim to use this chaos to build a state and call upon adherents to their brand of violent and regressive Sunni(esque) philosophy.

While these groups are less sympathetic than the IRA, early ANC, or ETA(to an extent), it's a mistake, I think, to view them as wholly different, or less human.

*Edit to clarify, these guys are definitely assholes and we need to have strategies to counter their goals.