Why does everyone's view of
     reality leave out some truths,

Maybe its because some truths follow from causal relationships:

For example:
          natural forces push every organism on earth
                     to use every available resource to
                         survive to reproduce, and
                              make life easier.
          The resulting demands for the earth's resources,
               from these forces
                    summed over all individuals of a species,
                         create the species' total footprint.

When members of a species have the same personal consumption
     (usually because there is little capacity to live above subsistence)
     the total species' footprint relates to the number of members.

The members increase in number until the species' niche is filled.
     After which:
          if the niche expands the population rises,
          if the niche contracts there is a die-off.
     This simple model describes the rabbit population
          on an island.

Humans are not like rabbits.
     Our population size on an island is described by additional truths.
          In our discussions of overpopulation problems and
                    behaviors that address them,
                              if we leave out these extra truths
                                        our scenarios are incorrect.

For example:
     1) Humans can increase their niche by consuming non renewing resources.
          With exhaustible resources, humans can support (within their niche)
               a bigger number than the niche can support after
                    the non renewing resources exhaust.

     2) Every human does not consume the same amount of resources.
          For the same total human footprint, there can be either
               a few individuals consuming a lot,
               many individuals consuming a little, or
               some mix of large and small consumers.

          When the niche is full
               any change in consumption of any individual
                    up or down
                         (assume most other individuals
                              holding their consumption constant)
                     results in a population change.

     3) Humans can increase the size of their niche by taking the resources
         from the niche's of other of earth's organisms.

     4) humans have cognitive abilities that create
          foresight
          variable technology, and
          self, social, and system conscious.

When we leave these truths out of our discussions
     the rapid rise in overshoot and
     the increase in the
          magnitude and
          probability
               of civilization collapse
just don't exist.

For example, because of
     1) the diversion of resources to attend to conflict
     2) the extreme and rapid stratification of wealth and
     3) the decline in renewable or non renewable resources
          that support the present human footprint,
the human experiment is (or soon will be) in overshoot by a factor of 100.

The meaning of this statement, if true, is earth shaking.

Consider
if
     the poorest 80% of the globe's population
          disappeared from the surface of the earth,
Then
     the 20% of the world's resources
          (consumed by these ~5 billion people)
               would be released.

This release means that the human community would then be
     in overshoot by a factor of 80 (instead of 100)!

Also
if
     the remaining top 20% of the earth's population
          (the group that already consumes
               80% of the earth's resources)
          would increase their total footprint by 3% a year,
Then
     it would take only ~8 years to
     return the community to 100 fold overshoot.

Alternatively consider,
if
     today's global population is not in overshoot,
          but is very near the earth's carrying capacity,
               (e.g., next year we will not be able to
                    increase food production,)
     and the world's rich
          (top 20% of the existing population)
     increased their footprint
          (from 80% of the supporting resources)
     by 3% per year,
then
     they would take all food from the world's poor in 8 years.