https://en.wikipedia.org/wiki/Civilian_casualties_from_US_dr...
Here. Is that sufficient, or would you like video evidence of every drone strike along with complete bios on everyone killed including family member testimonies about their selection for assassination?
"However, this does not represent new evidence. Stanford and NYU researchers made no attempt to offer new statistical analysis on the number of civilian casualties caused by drones. Rather, their report is essentially an extended endorsement of a database compiled by The Bureau of Investigative Journalism" - foreignpolicy article third source
To the last thing you state , yes it shouldn't only be just that, but more evidence. Unfortunately, modern journalism can't provide us with those very important details, instead only off topic sources that really don't care if they are one hundred percent correct.