They are telling provocative things on purpose. It is needed to create the fake debate that traps the public between two falsehood.
The heated tones and the strong arguments are meant to enrage people, drag them into the battle and push them to take one side and accept the arguments of that side without a proper deep thinking.
overpopulation is not measured by how many people you can pack into a telephone booth. Overpopulation in measured by how many people the Earth resources can support.
We began to consume more resources than what the Earth can provide decades ago, when the population was less than six billion people. Not just fossil fuels, we are consuming fresh water, arable land and forests in a non sustainable manner. The wild fish population in the sea reached an all time low and we are still overfishing. Fish farming accounts just for a small fraction of our consumption.
The alarms by the World watch and other institutes began in the '70s. Nonetheless the world population kept increasing and it is still increasing.