The problem is, though, journalists can't really say 'The Russians deny responsibility, but I don't believe them, and you know and I know that they're lying, and they know that we all know they're lying.'
The first casualty of war is the truth.
Journalists are supposed to report the news, not make it up. If they want to call the Russians out, they need to challenge them robustly, and they need some facts, some sources, for example, footage of incidents/attacks/explosions, eye witness accounts, testimony from doctors about injuries, information from arms trade researchers/munitions experts, etc.