1/3
1 Year of Service
Also worth noting that movies were NEW. Special effects were NEW. Nobody had ever seen the concept of a big scary alien, or a crazy serial killer, or a murder robot put to film before. There was strict and heavy content policies on everything in movies for a long time. Combine that with the semi-Puritanical social norms of the 1950s, and people were liable to freak out. The radio reading of War of the Worlds is another example that shows people had never seen or imagined this stuff before.I think you underestimate what anyones imagination still has to 'lift' even with modern movies ... everyone knows they are watching a movie, yet they get scared.
It's called (willing) suspension of disbelief, by ignoring the fact that it is fiction your brain acts as if it was real. And for how bad it was looking back then: it was (often) the best possible, so it didn't seem as silly at the time. Some old movies that are good made hold up pretty nicely even today (think of Jaws), while others that weren't the top of the cream back then might look too ridicolous compared to todays standards ... and only that direct comparision makes them too unbeliveable.