I wouldn't try anymore. People who outright deny the truth have their minds made up, the only thing that can sway them at that point is themselves. The more you push, the further away they get from you and become more solidified in their stance. Falsifying evidence only perpetuates the problem, say in the long-term it turns out that you were wrong: what then? You've changed people's minds on an issue under false pretenses and have damaged societal progression overall because we then have to go through the motions to get over that particular issue when that time could have been spent on something more legitimate. I don't feel there's a situation where it's ever acceptable, even if it seems right at the time. Even if you're right about the subject you're covering, you're cheating the people around you out of the experience of coming to terms with it on their own which builds a stronger foundation than a lie ever could. Even if it takes a generation for the change to happen, people are less likely to discard work they've personally put into something rather than having someone tell them "This is how it is". It's the difference between watching someone do something and learning how to do it yourself, you appreciate it more. The better long-term situation is to let the truth come forward on its own, lying to people to get your way is a short-term and self-serving victory under the assumption that you know better than everyone else. Present the facts, if they don't listen then let them sit in their echo chamber until they're ready to come out.