I think it means bot, bot, and moar bots.
It was mentioned in conjunction with DDOS attacks. That would suggest it the same basic concept, but maybe more sophisticated execution.
It may be too far away to see any kind of smoke trail.
Consider that this is a long exposure photo taken at 3am. It may have been VERY far away; but it looks fairly close do the the amplification of the apparent brightness of the exhaust plume.
But you're right.. that is curious. It makes you wonder, if it was so far away, why don't we see it arcing over towards a target? Perhaps the target is behind the camera and the missile is getting closer, flying almost horizontally at the end of this exposure. Image doesn't include the camera's compass bearing.
Chem-trails are almost surely cloud seeding. It's done with non-toxic chemicals.
https://en.wikipedia.org/wiki/Cloud_seeding