The reason you see what you see is because you use the verbose flag. As the manual man netstat states:
--verbose, -v
Tell the user what is going on by being verbose.
Especially print some useful information about
unconfigured address families.
Later the manual explains what netstat considers address families:
--protocol=family, -A
Specifies the address families (perhaps better described as low level protocols) for which connections are to be shown. family is a
comma (',') separated list of address family keywords like inet, inet6, unix, ipx, ax25, netrom, econet, ddp, and bluetooth. This
has the same effect as using the --inet|-4, --inet6|-6, --unix|-x, --ipx, --ax25, --netrom, --ddp, and --bluetooth options.
The reason those "no support for 'obscure address family/protocol' on this system" are displayed is that some of those address families, low level protocols, although supported by netstat are not supported on your system.
That is expected.
Not all protocols will be supported on a generic server, often because they are rarely used and/or for example because a particular protocol will only make sense with specific associated hardware.
I had look up the AX.25 Protocol ; that protocol (like NET/ROM and ROSE) is designed for use by amateur radio operators and usage on amateur packet radio networks; therefor not protocols that are commonly required to be supported by generic servers.
The kernel docs: https://docs.kernel.org/networking/sctp.html list the Linux Kernel SCTP (Stream Control Transmission Protocol) support as beta, so probably the reason why your Linux distribution also does not enable it by default.
If you want to enable support for those protocols: you will need to explicitly load the sctp or the rose | ax25 | x25 kernel module like below (as root or with sudo):
# modprobe sctp
and the informational message about unsupported protocols should go away.
