This is sad.
I don't want to be the devil advocate but I don't think we can judge here...So I will imagine the defense of Joe ;
I understand that Justine doesn't want to enter in details. But without all informations, it does seem to me that Joe could have just misunderstood Justine behavior.
"- Joe began to start rubbing my back and kissing my forehead (let me say this is not uncommon behavior between me and men I consider close friends."
=> Joe certainly believed that it was unique between Her and Him. He doesn't have the same pov as Justine
"- Joe then put his hands down the back of my pants, yes, I wear a thong and thus he began grabbing my ass."
=> Shouldn't she stop him there ?
"- Joe then started kissing me, forcibly with his tongue. I was not reciprocating."
=> Joe is drunk. He certainly does not remark that.
"- Joe began to put his hand down the front of my pants and finger me."
=> He certainly have gone to far there. But why does he wasn't stopped before and during that operation (not easy) !
"- I told Joe to stop and reminded him he had a wife and children. He said, “Don’t’ worry about it we have an agreement”"
=> That unfortunate, in one side (Justine), it seems to be the smartest thing to say to calm him down, in the other side (Joe), it seems like a girl who know it is wrong but wanted it if he is certain would said.
As for what we have here, it doesn't seem to me that Joe is specially an asshole (but maybe I'm wrong.), but more that this could be the results of peers pressure and mis-communication.
[Again, I don't want to judge here, just to give another pov]
It's however clear that Joe should have think about how his work relation [the fact that he is her boss...] influence that relation.
Maybe this is what the victims of assault don't tell the police. They fear that the case will be drop because of lack of details...
"- Finally Matt Darby approached me and asked if I want to go out for a smoke (I smoke, he does’t smoke, and I knew that he was trying to help) I agreed."
That's a smart move. Bravo Matt.
In another subject, I'm surprised (and sad ?) that HN doesn't give any tips, tools for all the possible victims.