Some people are being super nitpicky about very unimportant details here. The reality is that this episode was much more than I had anticipated so I for one was thrilled to say the least. Jackson went to the party because clearly he's not in control The Argents were busy dealing with Mrs. Argent and so they weren't going to crash any party, not that Jackson knows that but even if he did would it matter? no!
Anyway folks, the fact of the matter is that this episode was a solid 10 in many ways so don't let exaggeratedly low ratings fool you into expecting otherwise.