Earlier quoted context omitted.
You have invented a “harm principle” to be used when evaluating truth , and the fact that you think this is a cogent argument is scarier than anything Paul Graham might have said. One’s right to say something isn’t curtailed just because their saying it might intrude on your dogma more strongly than if it was said by someone with less social power.
If I'm following you correctly, you're implying that in order to debate with others to determine what truth is, you must have the freedom to say things without being bound by how the act of saying them would affect other people, right? And I'm disagreeing and saying that, unless you have some sort of prior agreement with the people involved (which social media/the internet/readers of your blog don't have), you don't…
However, science isn't the final arbiter for marking out the optimal societal norms, whatever those may be, although this seems to be the meaning of 'truth' as you use it in this context. An authoriarian state with zero personal freedom might be just as capable of feeding its human population as a libertarian state with a minimal set of legal restrictions, for example.