In fact it was intentional. The idea of Classic is to recreate vanilla WoW as close to what it was as possible, for better or worse as emphasized by Ian Hazzikostas.
Just as importantly, Hazzikostas says, is that Classic “is what it is” and that players have to take “the bad with the good”—even if that means missing a boat because a priest mind controlled you. "There is no lobbying the developer to change that because the game is what it was in 2005," he adds. “It has to be accepted, which then frees everybody to find all the positive aspects, all the upsides of that friction and those inconveniences because there’s a certain acceptance of the downsides.”
Classic is meat to be what it is. It is meant to be vanilla for better or worse. Like it or not that’s how it’ll be.