Externalizers tend to place the locus of control outside of themselves which symbolically castrates them to fantasize about the objet petit a[2]. When it negatively impacts your life, you become the friend who likes to complain about everything but does nothing. Or worse, you're a person against the world who owes no one and impotently rages against everything.
Internalizers do the opposite. They will place immense burdens upon themselves to unrealistically adapt and change when most people would confront the challenge directly. An example is the Missing Stair[3] metaphor. An internalizer works around everything, always pushing the problem inward and never forcing the world to change. Internalizers can be harder to identify as they silently suffer in an absence of self-kindness.
What the article glosses over is knowing yourself[4] well enough to understand which tendencies you have. Maybe you tend to be an externalizer with your career and an internalizer with social relations or vice-versa or some other mixture entirely. It can be hard to be honest with yourself and ask, "Is this truly working for me?" But, those questions are hard precisely because they are the first step towards personal growth.
1. https://www.psychologytoday.com/us/blog/the-theater-the-brai...
2. http://cahiers.kingston.ac.uk/concepts/castration.html
3. https://en.wikipedia.org/wiki/Missing_stair
4. γνῶθι σεαυτόν - which everyone should practice before blindly taking advice