That calculator includes an estimate of likelihood of catching covid - so the actual risk of hospitalisation for someone who does catch covid is way, way higher - for a 25 year old man in the US it's about 1.6%.
Ok, 0.008% if you want. Sure feels like an argument for argument sake. I can find a list of odds of things that will hurt/kill a 20-something where the percentage is greater than 0.008 if you'd like.
https://www.economist.com/graphic-detail/covid-pandemic-mort...