Why ifconfig command does not work due to permission denied when you connect to public WiFi or SSID?

This might be a bit stupid/naive question but I was at a conference event and after I connected to Free WiFi, I tried ifconfig in cmd of my cellphone via **Termux** and it did not work as follows:

> ifconfig
Warning: cannot open /proc/net/dev (Permission denied). Limited output.
lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 1  (UNSPEC)

wlan0: flags=4163  mtu 1500
        inet XX.XX.75.132  netmask 255.255.224.0  broadcast XX.XX.95.255
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 1000  (UNSPEC)

before writing this post I thought used ipconfig but now I'm more curious why they closed/banned ifconfig command. Do they close this command when they configure the DHCP server to provide free internet access for the public or thesis configured somewhere else? and why? **Edit1:** as @Mircea Vutcovici proposed and commented - I installed getfacl via Termux on my cellphone and tried getfacl /proc/net/dev; it resulted in: > getfacl: /proc/net/dev: Permission denied - tried ls -lZd /proc/net/dev, it resulted in: > ls: cannot access '/proc/net/dev': Permission denied