It’s the speed limit that isn’t shown in certain countries. The speed is shown.
There is obviously not any specific law against showing the speed limit. The legal issue is that the Google’s software for showing the limits is tied in with the speed control software, which is illegal some places.
Google just haven’t bothered make a custom version of maps for those places.
Also, they have had technical issues with the speed limit data being so wrong in some places that they rolled back the function shortly after it was implemented.