Simply access the video on YouTube, click the "share" button, copy the link that pops up, and paste into your post
I ran into the same problem with this forum software. When you copy & paste a URL from the URL line in your browser into a msg on this forum using the url tokens the video does NOT display. But, as Dan W says, if you click on the "share" word under the Youtube video a link opens up. Copy and past that link into a url token and the video will show and play on your post.
Concerning the video in the OP:
The Left KNOWS the difference between an assault rifle and other rifles. IOW, they understand the difference between a gun that can shoot many rounds with one pull of the trigger and one that can shoot only one round with each pull of the trigger. They are, with support from the media, pretending that there is no difference for NO other reason than to deceive the public.
They ALSO KNOW that banning magazines that can hold more than 10 rounds doesn't effectively slow down some crazy shooting up some theater because they, too, have watched videos or even fired semi-autos with small and large magazines as well. Again, they are depending on the media to make large capacity magazines into "scary" components in the public's mind, just like they are trying to label the semi-auto AR-15 an assault rifle because it looks like a real one and is "scary".
Then why are they pushing for these laws? Full confiscation is the goal. Each and every concession they get is another step to full confiscation. When they get so close that the next step is a small one ... it will be taken. We've seen the model work before in England and Australia.
The best approach is not to be RE-ACTIVE. It is to be PRO-ACTIVE. Don't just fight against what the Left is trying to pass, although that is necessary. Propose roll-backs in the infringements that already have been used to carve up the 2nd Amendment. Propose enhancements for open carry. Push for bills to remove the requirement to get a "purchase permit" in order to buy a firearm, or even background check requirements, propose bills the prohibit "gun free zones", including schools and churches.
The evidence is on our side. The assault weapons were banned in 1986. How many mass shootings have there been since then with an assault rifle? How many shootings were done by someone who wasn't mentally unstable? Everywhere local governments return to the 2nd Amendment crime in those areas go down significantly. Where guns laws are the most strict crime is the highest. Criminals don't obey laws and in those areas they know their chances of encountering an armed individual is low. With capital punishments so weak it is to their advantage to kill witnesses if they face life terms if caught again.
Why are English policemen now arming themselves with submachine guns even though guns are outlawed in England. If the government can't stop the flow of dope they can't stop the flow of weapons.