In my experience a "tech worker" is any employee working for a company that produces a "tech" product. I know accountants and lawyers that say they "work in tech" despite not doing anything technical.
I'm not saying I agree with the above necessarily but that seems to be the consensus. The gatekeeping, disgruntled programmer in me suspects it's a way for non-technical staff to inflate their salaries by sneaking into the tech bubble.
Here in the UK I find working from home more comfortable, but there are pros and cons to both WFH and offices. But I get about 3-4 hours back per-day that I would have spent on a train. I also save money on transport and lunches in London. Finally I'm able to work for companies across the country rather than everything being focused in London which is evening the playing field.