I'm not sure if you find it genuinely surprising that the Hacker News populace is not moved by a device that you not only have to pay rent for, but that also seemingly does not support custom ROMs/firmware.
Besides that, the software that they expect you to pay rent for is a fork of LineageOS/AOSP, but it doesn't seem to mention anywhere on the site whether they donate any of the rent to their upstreams.
Those are fair criticisms, but that's not what I saw mentioned when the thread was young and the comments were at the level of "wait I have to pay for them maintaining the OS??". It seems people have that as a gut reaction even though they have presumably also (on average) been exposed to sentiments pro paying for things that cost money
Besides that, the software that they expect you to pay rent for is a fork of LineageOS/AOSP, but it doesn't seem to mention anywhere on the site whether they donate any of the rent to their upstreams.