Yes, Barr should have prevailed. As he points out, the two major parties don't let 3rd party candidates on the ballot all the time due to "bureaucratic technicality". They should get a taste of their own medicine, and be told they aren't above the law.
Then they would have been placed in the awkward position of having to pass a law giving them ballot access.
Not really, since he's simply trying to maximize his impact in every state.
If the law says he should be on in that state, he should get on. If he didn't do what it says, he shouldn't get on.
Without consistency, there is no fair election. The Texas supreme court and the two parties proved so in this case. That law isn't written to apply to only 3rd parties, but apparently it does (3rd parties have been disqualified because of it in the past).
The law should be fair (same requirements for all parties to get on the ballot), and it shouldn't bend for ANY party if they don't meet its requirements.
Unfortunately, there was nothing fair nor consistant with what happened in Texas.