That was my take too. With 40+ years experience in software development and system administration, I don't know what to make of someone with obviously limited experience expecting to get a "senior" title or to pick and choose what they will or will not work on -- based on the
programming language involved. That the author tracked time spent in each language, worried about the meaningless job title, but then decided that maybe they aren't interested in e-commerce (Shopify's core business) shows a junior-level attitude.
When I studied photography I wanted to use new lenses, cameras, flashes, light meters, film. My teacher, a professional photographer, told me one day that amateur photographers obsess about equipment. Professionals think about lighting and composition. That stuck with me. Junior programmers obsess over languages and tools. Senior programmers think about architecture, data structures, team cohesion, requirements, business value.
I'm sympathetic to younger programmers who enter the job market faced with the stupid algorithm-oriented interviews, which are a kind of hazing ritual performed by people with such poor people skills and confidence in their own judgment that they fall back on pointless whiteboard tests that give the interview process the veneer of rational objectivity. Instead that kind of process just insures that everyone who gets hired has the same personality (or lack of).
A lesson to take away from this experience: The interview and hiring process may look like a serious attempt to find the one perfect candidate for an amazing job. Actually larger companies tend to hire lots of people who look promising, ignoring their work experience and desired career path, and just sift out the people who don't fit or can't produce. That's not new either. I started my career as a junior, hired along with more than 50 other juniors, assigned two mentors and allowed to sink or swim. Three months later only 15 of that group were left. Later in my career I mostly got hired through word-of-mouth and referrals, sometimes I was the only candidate for a job that wasn't even advertised, and usually I didn't go through HR at all. If you're still going through a funnel to get a job you are almost by definition not senior.
Note to the author: Almost every place I have worked in four decades, with a couple of horrible exceptions, let me run errands, take care of my kids, take as much PTO I needed, asked me to take time off if I was sick, and generally showed a lot of flexibility with what's called work-life balance. Only badly-managed groups and companies don't do that, and it's not a new thing. Given the ever-increasing demand for skilled programmers companies are forced to bend over backwards to attract and keep good people, so a manager who wants to keep their team will accommodate.