I'm not a Star Trek fan, so I don't necessarily follow that comment, but....

Having said that, I think you make a valid point, harsh as it may seem.    I think there most likely is a maximum population that this Earth can handle.  Not sure what that number is, or how close we are to it, but it seems logical that there is a maximum number of people that Earth can handle....

As for today, there are some areas where it is probably already too crowded, and some areas where it is not yet at that point.  The point being we currently have an uneven population distribution.  So, there are some areas where disease is going to be a bigger concern than other areas.