I am going to assume that you haven't really read the debate in the thread. If you have, and you truly don't understand it, let's talk about precedence.
A few short years ago all of Apple's laptop batteries were removable. Presumably this was because the battery has the shortest average expected lifespan of any component in a laptop, and therefore it is reasonable to expect a new battery will be needed before the product reaches end of life. Apple started soldering the batteries in the name of making the machine thinner (and maybe lighter, not sure if those claims were made) with the MacBook air. Now, ALL of their laptops come with a soldered, non-removable battery. Should this be something you want to service, you will need an Apple (or otherwise certified) professional to do it for you; certainly it is within the realm of possibility for many hobbyists, but for the average user, not so much.
Now we move forward to a soldered RAM which, to my knowledge, Apple hasn't come out and made any claims about why they went this route. Is the machine thinner? Lighter? Will this become the new norm? We have seen on this very site various configurations where it is cheaper to buy directly from Apple using configuration X and then upgrading with parts from company Y, rather than going with Apple's own upgrades. Are they testing the waters in order to see how sales go to perhaps, one day, move over to 100% soldered ram? Who knows? But that is the fear and discussion, for the most part, that is happening in this thread. Who is being served here? Is it the customer? Or is it actually just Apple?
I thought I would add my own experience with a late 2009 27" iMac. It came with 4GB of ram and 1TB 7200RPM HDD. Those were fine, at the time. I recently upgraded to 16GB RAM and a 250GB SSD with a 2TB external for media. In total, this cost me around $400, and I feel like I have a brand new computer. The RAM is easy for just about anyone to do, even a person who has never done it (jus ****ch a youtube video). The HDD to SSD swap was more challenging, and not likely something the average consumer would try and tackle, though it was doable. Even so, had either of these components been soldered, we would be talking about a new computer, more than likely.
TLDR: Today Apple stills sells a soldered and an end user servicable RAM configuration, much like they did with MacBook batteries, initially. There is absolutely risk of soldered ram bleeding into future releases of the higher end models of iMacs as well.