Having parity on a one or more separate disks is one of the hallmarks of RAID4, and as such the comparison conceptually makes sense even if it's not literally RAID4. The actual state of their data protection is actually worse due to data not being striped across the data drives, reducing I/O, causing balancing issues, limiting large file sizes, and increasing risk of data loss if the wrong drive is killed at the wrong time. Modern software RAID not only solves all these problems, but also automatically heals bit rot and often includes compression support for both space savings and increased throughput. Unraid stalwartly refuses to grant these protections and enhancements to its users in the name of "simplicity", which I as a storage engineer must balk at.

Put your data at unnecessary risk if you want. I will shed no tears for you.

I'm flagging you both.