Don't try to hide behind "it isn't violence". Everything is violence if you think hard enough. We just prune down the scope to what happens to be convenient at the time.
The real qualifier for what makes this "theft" is the asymmetry of value generated for the payer vs. the reward returned to the payee.
Think about if that janitor WEREN'T there. She just stayed home and hardened somehow. No more floor\workspace cleaning, no more trash being emptied, no more bathrooms being restocked, no more Windows being cleaned.
I'd like to see 90% of businesses that hire janitors workplace productivity after not having them around.
Now look at programmers. System's I develop transact billions of times a quarter, generating millions in revenue.
Suppose all of the people capable of developing those services refused to work as well? Things would go along fine for the most part. Millions would still roll in.
So, yeah. It's theft. In BOTH cases. We just like to draw lines between skilled and unskilled labor and say "this person is more valuable than that person".
It's why the phrase "Human Resources" became a thing. It isn't about doing business in good faith with someone else. It's about stroking egos and making the financials look good.
I don't know the solution, but when most normal people I know make 4 times less than the average programmer for an equal investment of their lives to someone else's ends, there is some stinking problem going on, and it isn't just "the market at work". That's a part undoubtedly, but there seems to be something structural underlying it all as well. There is no reason why wage growth should not have scaled with capacity to generate revenue.