Let's get this straight, out of the possible jobs that exist that require no experience, no education, very little mental or physical risk or exhaustion, this one ranks probably near the very top.
There are very many jobs that have the same requirements that don't pay as well or are very demanding physically, mentally or both. Why are some of the other jobs that have to exist quickly forgotten? Is it because of the exposure to the healthy and wealthier techie crowd?
Also, I don't know if you've ever had a job that's underpaid where you work with the public, but it's incredibly exhausting and frustrating and nothing like my comparatively stress-free job where I get to sit at a computer all day. Now imagine doing that in this moment of crisis where you're doing deliveries so that others don't have to risk themselves!
To your specific question, obviously something about Instacart will get more play on a tech site than, say, sanitation workers. I don't think that's odd. But there's no reason to assume that one needs to come at the expense at another -- if you start a thread about sanitation workers, I'd be first to upvote it.
As far as tipping goes, nurses are not tipped for their work. Nor are doctors. Tipping should not be part of the equation as it puts too much variability in the pay for these people. They should be paid based on the risk and the need for their work, not based on the whims of some people.
The market isn't whatever corporations tell you that you're worth.