Earlier quoted context omitted.
That's not realalistic for most of the Linux world. Soooo many systems are still using iptables even though we "should" be using nft everywhere. If you're going to be a Linux Sys/Net Admin today, you need an understanding of both systems.
If someone doesn’t know iptables, they probably are not required to know it. You wouldn’t recommend people to learn C++03, would you?
> If someone doesn’t know iptables, they probably are not required to know it.
That makes no sense. Just because I do not know X, it does not necessarily follow that I am not required to know it, not at all. I might need it for my job, or my future job. I might need it for a Linux distribution I just installed, and so forth. Or perhaps I am already using iptables, but I do not know it.