"I prefer this option (implicitly you presume that will be the taxation), but that if this argument is to be the basis for policy, then ..."

This is dangerous, in the real world. If you say "of these two options, I prefer X," I would expect that to be misinterpreted by non-literal-minded people as "I support X." In any real-world situation, I think it's actually smarter and more useful to say something like, "This is the wrong choice--there's also the option of Z" without associating yourself with one of the options you don't actually support. Similarly:

you surely should find one or the other branch preferable

Personally, I'm wary in general of the suggestion that I "should" intrinsically have a preference about something. I reserve the right not to have a preference worth expressing and being held to until I've thought seriously about the question, and I may not have thought seriously about the question yet. If I understand correctly, the original poster's point was that trolley problems do not adequately map to reality, and therefore thinking seriously about them in that way is not worth the trouble.