The reason that there were only about 40 people on those buses was simply because the UAF did not inform the people that there were buses also sent from Donetsk. The 40 people found them by accident.
I am not sure where you get your information to make the claim that the UAF didn't release the civilians.
As for deliberately shooting the civilians I highly doubt it. Most of those in Debaltsevo were conscripts and they are not there to massacre civilians. Generally the civilians that are dying are a result of indiscriminate shelling from both sides. The Ukrainian side obviously has the intent to destroy infrastructure as well which is why they also shell non militaryt targets.
I did not see any reports on the deliberate execution of civilians by the UAF. Provide a source if such a thing is true.
I am not sure where you get your information to make the claim that the UAF didn't release the civilians.
As for deliberately shooting the civilians I highly doubt it. Most of those in Debaltsevo were conscripts and they are not there to massacre civilians. Generally the civilians that are dying are a result of indiscriminate shelling from both sides. The Ukrainian side obviously has the intent to destroy infrastructure as well which is why they also shell non militaryt targets.
I did not see any reports on the deliberate execution of civilians by the UAF. Provide a source if such a thing is true.