A UN committee is equipped to go beyond simply reciting what secondary sources say. It can conduct it's own research, and carefully compare different secondary sources. So it makes sense for them to want to hear from people that sometimes say interesting things but aren't always reliable.
I don’t know what “employees of the Russian government” you’re talking about (maybe RT articles?) but I’ve watched WaPo and NYT perpetually without criticism or follow up publish White House and State Dept. talking points.