Standard commentary on Invasion of the Body Snatchers revolves around politics, the McCarthy era, the mindset of America hot with H-bombs, Soviet spies, a Red China, a Korean War stalemate.
The film is seen to warn us against creeping state centralization and the loss of individuality.
A counter-take sees the film warning us against the virulence of conformity imposed by fear, how judgment is clouded, how vigilantism destroys a society.
What about something more 'personal'? After all, the story centers on two intelligent adults whose potential love circumstance destroys. Subsidiary relationships among other characters wither, too, as precursors to the main. Father-daughter. Mother-son. Husband-wife.
The only virtue is survival, mass survival.
The clip where Carolyn Jones sees King Donovan's shape and soul inhabit the 'pod' found nearby. The opening of his eye, a 'first sign' of life, an alien life. She is to lose her husband, just as all are predicted to lose human bond to all others.
This world poisons all love.