This is in the private address space like 192.168.0.0, blocking doesn't make sense in this context.
Most people who are only vaguely familiar with networking seem to be able to remember 10/8 and 192.168/16, but the 172.16/12 range is for some reason rather elusive --- I suspect it's not as commonly used as the other two.
I think it usually gets used by VM/container networks (maybe there's some historic reason)? I have seen it once used on a hotel WiFi network (as I was unable to connect because of docker conflicting).
Not sure i'm following what you mean , could you elaborate further ?