As a European, I was surprised, too. But the key thing to remember here is that he pissed off some very influential people, so it's likely they stuck him in a maximum security facility with a lot of hardened criminals and some instructions to make his life as difficult as possible. Which is par for the course when you're an activist I guess, and a borderline-but-not-quite political prisoner. If you're someone who gives the authorities a hard time, they'll in turn give you a hard time, such is the nature of political corruption.
However, it's important to keep in mind that his sentence is only 10 months, which may not even be served fully. Those months are going to be bad, but the guy will return to his normal life pretty soon. He's a community hero, and financially taken care of, so there's probably not a lot to be worried about in the mid to long term.