If you look toward the start of the plume you will see the wind has spread it out.
Sorry but the “start” of the plume is down at the surface of the ocean and is unseen, lost in haze (as you can see) or over the horizon. The video shows the middle to the end of the missile launch.
“I watched that video more than 10 times: it is an SLBM missile launch. Any Air Force or Navy squadron in the world will tell you the same thing as I am telling you”.
I will say again, that is a contrail of a jet aircraft. That ‘plume’ starts in cloud/haze on the far horizon, not the ocean, and the aircraft travels from west to east toward the observer. It is moving far slower than a ballistic missile would at that stage after launch. Matter of fact, it is moving exactly at the speed of a transoceanic 4 engined jet. It only looks like the ‘plume’ starts at ocean level because of the curvature of the earth. You'd be amazed at how much of a curvature correction has to be computed while tracking a target a mere 200NM away.
The start of the contrail is at 30+K in altitude, which is why it exhibits all the characteristics of being influenced by high altitude winds. That cannot happen at the surface. The aircraft also was fighting those winds, requiring multiple small course corrections northward to keep proper heading. It can be seen in the contrail. A large front was bearing down on the coast at that time, which is why it looks so strange.