Couple of things I didn't like

Well, let's see. They blew the thing up with thermite and stayed away from the saucer. Many of these men had seen combat and knew what bomb-induced explosions can do. They were also very familiar with second dary explosions.

Now, given what they know, would you want to go over and "look through the hole" and risk the possibility of a secondary explosion?

Also, you have to understand the audiences in 1951. The American public was not acclimated to on-screen violence as we are today. In those days, newsreels were heavily censored during the war and afterwards because the news organizations were afraid people would go out and get popcorn rather than view a plethora of dead, dismembered bodies. Many in the audience were women, and others may have been war veterans who had see such gore and were suffering from Battle Fatigue, what we today call PTSD.

Now days, we see the results of extreme violence on the news broadcasts that come into our homes. So the censorship that didn't allow viewing of the hand was in line with the mores of the times.

But they did show it. Look at the movie again and you see it being fully shown when someone picks it up outside. If you saw it once, why would you want to see it again? In the next scene as it is being examined, why see it again. Use your imagination to think of how it looks.

"Do All Things For God's Glory"-1 Corinthians 10:31
I try doing this with my posts

Using the mans body to block the rest of the dismembered hand was to block how they made the fingers move - this was the early 50s not the early 90s. The story, not the special effects, is what counted.