Maybe he wanted you to STOP BOTHERING HIM.
No need to chuck a hissy because of it.
You do understand that all I saw was a login and then I talk. 90% of the time, that means you're free for 3 seconds. But he says "Stop bothering me" for little reason, which seemed uncalled for.
"I'm busy" would make sense, "Stop bothering me" implies I was being much more annoying then it seemed.
And he blocked me, why? You shouldn't block someone for this, why? You'd just log off, or in his case, he could have set Appear Offline. He didn't need to block, and now he won't remove.