There are about 200M adults in the US. If 1% of adults hold bizarre and delusional beliefs, that's 2M nuts out there. In the olden days, you would bump into one of those people from time to time but it probably wasn't a regular occurrence. Today, though, those people have access to social media. It turns out that nuts are drawn to hot takes, and the social media infrastructure operates as if it were intentionally designed to amplify these folks. Sane, level-headed analysis gets read and forgotten, but crazy-wild insanity gets re-tweeted to the heavens.
There's nothing wrong with laughing at this person -- it's probably healthy to laugh off nutty opinions. But it's not healthy to turn episodes like this into a Two Minutes Hate, because mathematically somebody similarly nutty is going to show up in your feed basically every day and it's not good for anyone's psychological well-being to walk around outraged all the time.