Why can't I click 'Agree' on terms and conditions when signing in with Apple ID?

When you reach a panel which says:

Sign In with Your Apple ID

if doing so with email and Apple ID / iCloud password

(not the UNIX system one)

and clicking Continue leads you to a panel which says:

Terms and Conditions

A. macOS Software Licence Agreement

More

B. Game Center Terms and Conditions

More

but it has Agree greyed out so you can't click it

What you do is click Back to return to the panel which says:

Sign In with Your Apple ID

and in blue below this there is an option to say

Set Up Later

Click this to go to the panel which says:

Terms and Conditions

A. macOS Software Licence Agreement

More

Click More and scroll through this if you need to (however it may already be showing the whole Agreement) and the Agree option will no longer be greyed out, so feel free to Click Agree

A drop down menu appears which says:

I have read and agree to the macOS

Software Licence Agreement

Where you have the options to Cancel or Agree

Click Agree to reach a panel which says:

Create a Computer Account

make sure you write down your new Account Name and new UNIX system password and new Hint

You can set up iCloud later through System Preferences

Take this opportunity to back up your important files to an external drive

THIS IS A REPOST OF A QUESTION NO ONE ANSWERED CORRECTLY

WHICH I WAS NOT ALLOWED TO ANSWER - HENCE THE REPOST

[Re-Titled by Moderator]