Although that also describes another beverage, coffee. The difference between the coffee and soft drink industries is interesting though. Two massive corporations dominate almost the entire soft drink industry, with a handful of minor providers (notably Keurig Dr Pepper) and a long tail of much smaller 'boutique', novelty, or regional brands. Comparatively, no coffee company controls as much of the industry as either the Coca Cola Company or PepsiCo do.
(Also, PepsiCo in particular owns a ton of other non-beverage brands. Their subsidiary Frito-Lay produces the brands Lay's, Cheetos, Doritos, etc. PepsiCo is huge for American consumers. To your point though, snack food isn't much better than sugar water.)
You can make the same argument for anything, from butter to guns to video games to literally anything that plugs into the wall and consumes electricity.
Use anything beyond reason and it becomes destructive.
Amazon also runs an entirely separate and special cloud staffed only by US citizens to assist the military in running software that decides who to detain, torture, and possibly murder, so it is unsurprising that they have no corresponding aversion to media depicting less violent interactions.
Isn't that the case because mainstream American advertisers don't want anything to do with it? I don't think it's a matter of west coast tech companies being prudes, but rather tech companies appeasing big consumer goods companies that spend billions on advertising, like P&G, J&J, PepsiCo, etc. And those companies are in turn likely appeasing 'middle america' by trying to keep their brands as bland and "family friendly" as possible.
Edit: (And now that I think about it, I'm pretty sure Amazon sells pornography, so that's one of the big tech companies at least that is willing to. And I don't think it's a coincidence that advertising from those big consumer goods companies isn't nearly as important to Amazon... Then again Amazon doesn't allow nudity on twitch, which perhaps could be considered roughly analogous to Google's similar ban of pornography on youtube. Perhaps twitch, as a consumer brand, is subject to the same social pressures from the American public as PepsiCo?)