You don't need to click a resource for it to potentially cause harm, the browser simply loading the resource would be enough. That is precisely why Chrome and Firefox blocked the entire threads from loading. Someone with Russian Rocket's technical expertise should be the first to confirm that, which is why his reaction has been somewhat surprising. A guy who accidentally posts harmful content typically doesn't berate your staff and explain how much damage he could have done if he wanted to. That doesn't quite pass the smell test.
Here are the warnings that the posts Russian Rocket made caused; the domain name has been redacted for your protection:
Our tech team is completing their review of his posting history. It would be irresponsible to allow him to make new posts during this time as much as you guys may like him. We will update once this review has been completed.