There is no other explanation for why authorities would limit the features of messaging apps. What's even stranger is that Messenger app from Meta is allowed, while the features of WhatsApp, also from the same company, are limited. In any case, these measures are meaningless in reality, given that people use all the apps. In the age of the free internet, imposing such restrictions is absurd, especially when no alternatives are offered.
The era of free internet ended 10 years ago. The authorities try to interfere with any established processes, but they need time to control them everywhere. Even 10 years ago they didn't care about messengers because it was like one of those things that come and go, but now everything has changed, more algorithms, more data, more control and, of course, more extensive appetites of the government.