My general take on the best practices is that any member of the development team should be able to perform any action on the tree presuming those actions don't do things like kick off a production deployment. In cases where a specific branch / tag / repository does act as a source for automated deployments putting in some reasonable change control or barriers to entry make sense, more from a keeping mistakes merely mistakes perspective than some control-freak angle. I would encourage developers to create branches and improve the build scripts. I would find ways to get developers access to production if needed. Part of the point of source control is it is an effective magic eraser of mistakes -- the worst you'll need to do is roll back a rev or two and branch off that.
Unfortunately this doesn't sound like the approach they have taken here. In order to defeat this I think you need to cover a few angles:
a) Prove that these policies are detrimental to developing things. Log all the time you spend waiting on ops to get working on something. This alone should sell reasonable management on why this is a bad policy.
b) Make some friends in Ops -- perhaps there is a reason for this policy. Perhaps that reasoning could be addressed in a more effective manner.
Hope this helps.