The moral outrage crowd in the US have no power. The people who can and will act against you will only use morality as an excuse, not a cause. Being some nobody, the government has no interest in you anyway. You can watch porn, they can know it, and nothing changes, because you're still a nobody.
(If you watch porn online, you can be pretty sure they already "know" it, because you're not doing it in the privacy of your own home, you're doing it on a public network with next to no secrecy about who you are or what you're doing).
The hypothetical government isn't going to make stuff up about me, some nobody, on a flight to the US to be a tourist or something. They statistically don't care about me. However, the US morality police might decide to statistically care about everyone who watches porn.
But if I'm a somebody, say a former or potential whistleblower, or a local politician, etc. then a government might have a specific motive to do me dirty and not care about being honest.
I guess there's a wide and blurry line between being a "nobody" the government has no motivation to lie about and being a "somebody" that deserves special malicious treatment.