I think the difference between the two is Amazon and Meta do provide some utility to balance it out, whereas gambling is purely a net negative on society. You can be young and naive enough to believe you're "making the world a better place" in big tech. You can't work on pure gambling products without being a scammer at heart; you know what you signed up for.
This comment would make more sense if it were before the new wave of prediction markets, which are high-profile gambling products clearly largely made and popularized by true believers who think they are making the world a better place.
Nothing Meta has done comes remotely close to paying for the damage they've done to individuals and to society as a whole. I think the metamates know exactly what they're doing. There are innumerable documents with people at all levels admitting to literal crimes and how best to cover them up or minimize them. These are the types of people you wouldn't let into your home for fear of things going missing.
You can, because the definition of gambling is loose. Magic The Gathering is gambling. You by a pack and hope you get a valuable card, no different than buying a lottery ticket and hope you win. Pokemon Go is also gambling. You pay to hatch eggs and hope you get a rare pokemon. I'm pretty confident the people who made these games don't consider their design to be evil or wrong. In fact, I'm sure they see themselves has having provided millions of people with fun entertainment.