Not OP of that particular statement, but in Germany you can get imprisoned for denying that holocaust has happened.
However, I would question whether denying historical facts is an opinion. There seem to be fewer cases of people demanding that the holocaust should be resumed. That I would call an opinion. I assume that it would lead to prison if repeated often enough, albeit based on a different law. Still, I am more willing to travel to such country than to a country requesting my passwords at the border. Call it illogical or not, it's my preference.
> However, I would question whether denying historical facts is an opinion.
Historical facs have a tendency to change based on the current political climate. Which is to say, they are always more like opinions.
Although a better example would be insulting a police officer or politician, which can include as bening things as making fun of them on twitter. Granted, this is more a concern for citizens than it is for tourists so I agree with your assessment that the US border controls are a bigger threat to you as a traveller.
However, I would question whether denying historical facts is an opinion. There seem to be fewer cases of people demanding that the holocaust should be resumed. That I would call an opinion. I assume that it would lead to prison if repeated often enough, albeit based on a different law. Still, I am more willing to travel to such country than to a country requesting my passwords at the border. Call it illogical or not, it's my preference.