Because most humans are functional enough to understand the concepts of metaphor and allusion.
No rational person would read this headline and assume that some cosmic force prevents you from coding Dwarf Fortress unless you have a math PhD. Therefore the most reasonable conclusion is that the creator of Dwarf Fortress does have a math PhD, and that it provided significant transferrable skills. That this is not what the headline says on a literal reading does not prevent a reader even with zero familiarity on the topic from correctly understanding it.
Because the creator himself specifically addressed the headline in the article. So either you think you know better than the creator, or just saw the headline and knee-jerk wrote a comment without reading the article contents.
Saying "You don't need a PhD you just need to believe in yourself", or whatever, is fine - but it's not related to the article, so gets down votes.
The headline is part of the article. You could say “so you think you know better than the author” by quoting the body or “so you think you know better than the subject” by quoting the headline. Both are quoting the article to react to other parts of the article. The fact that the single most salient and most read part of the article sucks is plenty worthy of criticism.
Why is this normalized?