Despite all the advice, I’ve been washing knives in the dishwasher for a decade and they are still totally fine. They certainly don’t “rust”. What kind of metal are these people making knives out of?
1) It can be dangerous for anyone reaching into the dishwasher not expecting to find a sharp knife. If you live alone and no one else reaches in there and you're always at maximum vigilance, you do you. But I've known two people who got their hands and wrists sliced open horribly by sharp dishwasher knives.
2) Every stainless steel kitchen knife I've ever seen where the person regularly put it in the dishwasher had an edge that was so etched and eaten away that it basically looked serrated. Sample size is probably 20 for those. Knives I've seen where the person never put them in the dishwasher may have had a few dings and nicks, but they never looked like their edges were being dissolved away. Note though that this isn't necessarily a bad thing if you don't have an emotional attachment to the knife. A serrated knife is basically sharp on its own for free without sharpening.
3) Even if the blade isn't appreciably harmed, the rest of the knife made of other materials can be, and the handle could crack, loosen, or weaken. This depends on how the handle is made and attached.
4) Fancypants non-stainless steel knives do exist and will rust. (see e.g. https://www.reddit.com/r/Bladesmith/comments/bj63yu/this_is_... ) I don't really get why anyone likes them though.
The non-stainless alloys will have an easier time taking and keeping a very sharp edge. This makes them more useful, and for longer. Not only does a very sharp edge make the knife easier and faster to work with, is safer to use than a not-so-sharp knife.
As for your fourth point, soft metals sharpen in a few seconds. My high carbon steel knives will slice right through tomato peel without smashing the tomato itself; or cut raw meet in one quick movement.
https://www.amazon.com/gp/product/B008M5U1C2/ref=ppx_yo_dt_b...
These are highly recommended for a being cheap yet good chef's knife. Mine has survived 5 years of daily dishwasher cleaning...
I do not dishwasher mine, however, and I do not soak them.