Why isn't Grsecurity being sued for its long standing GPL violations?

[gameonlinux]

Hi, RMS and Bruce Perens;

I noticed that recently Grsecurity's Brad Spengler (who sued you, Bruce, 
for speaking the truth), decided to "Flex" and basically advertise while 
chastising the linux community:

news.ycombinator.com/item?id=20874470


Another poster then pointed out the history of Grsecurity's copyright 
violations (as a derivative work that is restricting redistribution), 
but said he didn't want to say to much, because he didn't want to get 
sued. He referenced your good write-up on the situation: 
perens.com/2017/06/28/warning-grsecurity-potential-contributory-infringement-risk-for-customers/

(Which has not changed)

Why isn't Grsecurity being sued for it's copyright violations? They've 
been going on for years now. Clearly their scheme works: it can be shown 
to a court both the attempt to restrict redistribution was tendered (the 
agreement) and that said attempt has been successful.

Also isn't Open Source Security simply an alter-ego of Brad Spengler? 
Him being the only employee? Couldn't the corporate veil be pierced and 
he be found personally liable for any damages?