My gut feeling here is that Elastic is probably right. The SQ team is very small, while that doesn't mean anything it does make you wonder.
On the other hand, does anyone know if a company that small has any viable way to defend themselves against someone with deep pockets like Elastic?
The Search Guard code has been taken by Amazon and rebadged as https://github.com/opendistro-for-elasticsearch/security
So they're not really fighting Search Guard at all. They're fighting Amazon with this.
And Amazon would probably (and certainly has the money and business case) to rather buy out Elastic than to lose this lawsuit by proxy - and maybe that's what Elastic is actually playing at.
Of course, ES and Amazon have been fighting a battle (of words/ideas/dislike) for a while now, since Amazon released a hosted ES, and an ES distro. So this is part of that battle.
https://www.cnbc.com/2019/03/12/aws-open-source-move-sends-e...
I still think however that Amazon will feel very involved.