Regardless of all the wriggling you are trying to do about what is implied and what isn't, you said 2 things that are not correct.
Firstly.
Photo stream photos are actually in the camera roll and what's in the photo stream folder is just a link to those in the camera roll. If you deleted them, you also deleted the original in Camera Roll.
Never mind whatever it is you find preposterous, what evidence do you have for what you did say word for word.
Based on what Apple actually say themselves (as per the screenshot I posted) and my own experimentation, it seems to me that it is not the case that photos in the photo stream album are just links. This is what I have done to bring me to this conclusion. Exactly what have you done to support your position.
Prior to testing, all my devices used iCloud Photo library, my 2 phones and my iPad were set to upload to photo stream, which was for the benefit of my Apple TV's not my Mac which had photo stream turned off. This was of no use for testing since the photo stream album is hidden and there is no camera roll when iCloud photo library is turned off. So in order to test my responses here in the communities as Apple suggest I do before posting, I take the step of turning iCloud photo library of on my second phone and making it my test phone.
After a while it removes the 20 thousand plus photos I had on there from iCloud photo library in "Photos" (at the bottom of the screen) and also removes the "All Photos" album from "Albums" (at the bottom of the screen) and creates a "Camera Roll" album and a "My Photo Stream" album in it's place. The my "Photo Stream" album has a whole bunch of photos in it which take up 711 MB. This makes sense at this time since these are photos that my other phone has put into "my photo stream" over the last 30 days and since the originals are not on the test phone they can't be just links to the originals and in fact are the low resolution images from the cloud. I assume you don't disagree with this assumption at this stage.
OK, but we need to see what happens when I take a photo on the phone and we are then in the position where the original is on the phone, so I start by taking a screenshot. The first thing I notice is that it immediately appears in the "Camera Roll" Album but takes about 30 seconds to appear in the "My Photo Stream" Album. Now that kind of looks to me like I'm waiting for the photo in the "My Photo Stream" album to download from the cloud after being uploaded from the "Camera Roll" rather than it just creating a link.
OK, to rule out the possibility that it just takes a long time (30 seconds) to create a link, I turn off wifi and take another screenshot and wait and wait and wait. After about 5 minutes, I still don't have the new screenshot in the "My Photo Stream" album, so I turn wifi back on again. 30 seconds later I have the screenshot in the "My Photo Stream" album.
OK, this is rather looking pretty much done and dusted in favour of low resolution downloads rather than links to me, but to rule out the possibility it might be because it's screenshots and not camera photos, I repeat the tests with photos from the camera. I take 4 photos in rapid succession, the 4 photos appear immediately in the "Camera Roll" Album but it takes almost a minute this time before the first photo appears in the "My Photo Stream" album (makes sense if it has to up/download since photos are larger than screenshots) and the rest of the photos appear in the "My Photo Stream" album in similar intervals. Oh and the same thing occurs if I turn wifi off as it did when I turned it off for screenshots.
I'm now pretty convinced these aren't links, but hey perhaps creating a link takes ages and for some reason gets paused if there is no wifi (not likely I think, but hey, lets be exhaustive about this). So then I think to myself, I've taken about 30 photos since I started testing, some are screenshots and some are photos, if they are links they won't take up all that much space will they, so I take a look to see how much space is now taken up with "My Photo Stream". It's now 733 MB.
OK, so that's 22 MB for around 30 or so photos. I see no other explanation for this other than "My Photo Stream" album has it's own photos. It would be quite ridiculous to use links that use as much space as an actual photo.
Secondly, you also said.
Photo stream photos are actually in the camera roll and what's in the photo stream folder is just a link to those in the camera roll. If you deleted them, you also deleted the original in Camera Roll.
Well now, this is kind of important since this was the crux of your advice to the OP, since the bit about links was merely supporting this advice. But hey, that's kind of easy to test now I have my phone set up this way, let's just delete a "My Photo Stream" photo and see if it also deletes the original in the "Camera Roll" album. No it doesn't, no surprise there then (at least for me).