I can't - if anything you'd be better off protesting to the treasury or your MP - but neither will make any difference.
Why can't you? If a business is not being taxed what it should be, and that sum is a large portion of the education cuts we're facing and we are on a demo that follows a route with a vodefone on it we're obviously going to be pissed at Vodefone for their tax dodging, it makes sense as to WHY we'd be there, not if its right, wrong or useful.