ELI5: Why do sex offenders in other countries get more lenient sentences than those in the US.

About 6 months after Jared from Subway got sentenced to 15 years for child porn I was reading an article about a guy in the UK that made Jared look like a saint and he only got 14 months. So my question is why is it that other countries don't punish people as harshly as the US?