It's a fabricated propaganda point.
> The fighting continued, the civilians were dying, children as well as adults. OSCE statistics (2017-2020) showed that the number of civilian deaths in the occupied territories was almost twice as high as in the unoccupied territories. Another independent report from the International Crisis Group gives the following explanation: “The higher civilian casualty rate in non-government-controlled areas is due to the fact that these places are more urban and populous[…] Together, the numbers suggest that neither side is trying to hit civilians but also that combatants are not doing all they can to avoid collateral damage.”
> The death of the children should be addressed separately. “Why were you silent for eight years while children were killed in Donbas?” sounds as if Ukrainian army is shelling children. But OSCE suggest other causes of death: 87% of boys died because of being careless with explosives. In this context, the International Crisis Group also recalls Russian propaganda, for example, when “they announced that a Ukrainian drone strike had killed a five-year-old boy in a Donetsk suburb. In fact, the boy had died some 15km from the front, out of the Ukrainian drones’ range, possibly by setting off an unexploded shell he found in his yard.”
> According to the OSCE, mines and other unexploded armaments are the second most common cause of civilian casualties in Donbas after shelling with heavy weapons. The international crisis group criticizes Russian militants in this context: “Meanwhile, de facto officials tend to be unwilling to admit that shooting from positions in areas like the Donetsk suburbs can provoke return fire and lead to civilian deaths. They have baulked at suggestions that they move their troops to keep locals out of the line of fire.” The shelling from residential areas of the occupied territories was also reported by Bellingcat. On the other hand, the International Crisis Group blames Ukraine as well: “Public figures in government-controlled Ukraine sometimes overlook or minimise the problem of civilian casualties from live fire. Losses among civilians frequently do not make it into Ukrainian news reports, partly due to journalists’ lack of access to reliable sources in areas across the line; media tends to focus on the heroism of government troops.” It is possibly the only argument in favor of “eight years of silence” claim.
https://rpr.org.ua/en/news/eight-years-deconstructing-the-mo...
If you look at the casualty figures, the civilian deaths have been around two dozen per year for the last few years; half of those have been from mines and such. About half the remainder have been from active hostilities, e.g. shelling. Russia didn't start this war over six civilians a year dying from shelling in Donbas.