I'm a little surprised myself, as someone who's trained in MA and used to carry a license in case I got into a fight with serious consequences, it seems pretty clear to me that he murdered the guy. Penny initiated the physical confrontation, struck the first blow. The other dude was not armed.
The hold he had the guy in (including the leg wrap) is designed to kill, that's what that hold is taught for in MA and military training.
He could have confronted the man directly and reacted as needed, but he approached him from behind and throttled him to death.
Of courser the jury saw more details than I did, but as someone who has been taught these things I consider his use of force excessive and unnecessary, physical force should only be used when absolutely necessary for protecting life and this didn't reach that bar.
This sets a precedent and does not bode well.