there are reasons and ways to be straight edge that are political. people's attitudes towards drugs in general and alcohol in particular are as dismissive and thoughtless as people's attitudes towards other things/tools/bodies in this culture.
if straight edge is a challenge to that, then it is a political act.
but most straight edgers i know are xxx because of demons in their past, which makes it more personal than political (pardon me feminist godds).
and to the extent that straight edgers proselytize then they are political in a bad way (see christianity, dogmatism, purism, etc).
(ps: this is different from being clear about it not being fun to hang out with people who are high when you are not high, or disappointing that so many people only know how to have a good time when loaded. for which, see first paragraph.)
omg edited to fix then/than problem! eeek.