I'm sure the neo Nazis did gatecrash, rather than being invited.
I think that was predictable though and I don't think KJK does enough to distance herself from them. In fact she does lots of things that makes her attractive to them (e.g. appearing on Carl Benjamin, tweeting and retweeting a lot of "2 tier policing" and Islam questioning content, vocally supporting Donald Trump as "the only hope for the world")
I can see why it would be an issue to the Liberal Party for one of the members to have a close and public friendship with someone who does these things and I don't think its defamatory for them to question whether she's an appropriate member of their party, especially if their voters and supporters are complaining about her.
There is an element of tunnel vision happening here in my opinion, by focusing on the Neo Nazis, rather than seeing the bigger picture (how should an organisation deal with a member going outside their values and when is it defamation to do so).