Presuming we're limiting "you" to young males, but including "couch to marathon" types, I have more issue with "12 months" than "sub-3". Starting with someone who hasn't been running to a marathon in a year isn't a person who is "trained properly" in my mind.
As for why this sort of post comes up repeatedly, I attribute it to a "everyone faster than me is doping/more genetically gifted everyone who is slower than me doesn't train hard enough" worldview. That is, I've earned my place in life, everyone else is either lucky or lazy.