Of course there was an earlier incident, no so much "railroad" as "DM attempts to enforce his own twisted morality on the players" which would probably have made it his last time too:
So usual adventure stuff, then after fighting some orcs we find there are some baby orcs. They are harmless and pathetic by the DM's description (in fact, he emphasized how pathetic they were). So we, being not monsters, decide they're now basically orphans, so we'll take them back to the local church of some nice-guy loves-the-weak deity and they'll look after them (one of us is a cleric there). The DM flips his chips. He never questions the premise, in fact he agrees that said church would take care of them, but he demands that because we are good-aligned, we have to murder the baby orcs. Raising them good isn't enough. They are apparently inherently evil. This is in the FR, where orcs are not inherently evil, just tend that way, note, and that had been established even back then.
So we're just refusing to go with this, and he has his GMPC Paladin turn up, zap all the orc babies somehow (to our utter horror!), and then attempt to tell us off (which was a bit like Genghis Khan trying to explain to some peaceable monks how THEY were the evil ones!). Le sigh.
THIS is one of MY pet peeves - anyone (Player or DM) who wants to commit evil acts in the game and then try to claim said acts are actually "good" because the victim is of an "evil" race, or a member of the "wrong" group... even if the victim is a child, helpless, personally Good-aligned, pleading for mercy on hands and knees, etc. (And why are only Humans and Demi-Humans entitled to a trial in a court of law if accused of a crime? An Elf clubs an old man over the head and takes his money, and the Paladin hauls the Elf to court. A Orc does the same thing, he's slaughtered on the spot, no questions asked. Maybe it's just me, but that seems racist.)