You're right, it is amazing. These people are giving honest constructive criticism of a product. Companies often have to pay money to get that information. These complaints are generally valid as well.
The company's commitment to repairability is commendable but it's in lieu of other important factors. If I have to make the choice between having the newer OS with stronger, more powerful hardware or the ability to repair my device I'm going to choose the former every time. From the get-go the device might last longer simply because I won't want to get rid of it as quickly. The 5 is of course a significant improvement over previous releases but it's still behind. If they can deliver a device that is not immediately outdated in comparison to other phones of similar price then this would be a no brainer for me and likely others as well.
Similarly availability is another major factor. You can't buy what you can't get your hands on. Even more importantly it's even more futile to buy one for a network that doesn't support it at all. Obviously the creators just aren't ready to expand into another market and that's fine but it doesn't make the criticism any less important for their mission.
Ifixit gives fairphone 5 a 10/10 on repairability and maintanence ( www.ifixit.com )
While they were happy with what the fairphone 4 brought to the table, they seem to like what was changed for the fairphone 5....