But physicists don't ignore friction when performing experiments, they do so only in teaching. If philosophers used trolley problems only to teach ethics ("Push one fat philosopher onto the tracks, to save two drug addicts.") or to teach metaethics ("An adherent of virtue ethics probably wouldn't push") then I doubt that lionhearted would complain.

But we have psychologists using trolley problems to perform experiments (or, if from Harvard, to publish papers in which they claim to have conducted experiments). That is what I understand lionhearted to be objecting to.