Due to the on-going virus outbreak, many employees will have to work from home with students having to study from home as well in which school resort to having online classes. Unfortunately, many students weren't happy with the fact that they had to go for online classes after the Lunar New Year holidays ended. There was a rumor that review-bombing the app with tons of 1-starred reviews would cause Apple to take down the app from the App Store, so the students found a way to fulfill that rumor although the Android version is still intact. Plus, not all students have a mobile device or something to begin with but that's not the point.
Some problems the Dingtalk app involve the collection of personal data or some sort according to some other tech site I discovered. I don't think Softpedia mentions that for sure. Another problem is how serious the situation regarding the virus outbreak is even today as well as other problems the students encountered when using the app.
Because the app was taken down from the IOS App Store, the company came up with the apology video, begging users to rate the app a 5/5. Also, the removal of the app would get the employees using it concerned since it is an enterprise app in the first place, not some educational app. If not for those problems I mentioned above, the app itself could be great or even excellent for anyone to use for work.
Obviously, review-bombing a product for immature reasons is one-way to get yourself investigated like some autistic and immature individual who did that to AI: The Somnium Files but for this case involving DingTalk app, the actions are outright questionable.
