Okay, so I watched the video and it's completely biased and negatively juxtaposed. Having permits for peaceful protests has been law for decades now. Decades. You can still peacefully protest in almost any area without a permit, but for some high traffic and volatile areas, you need permits. It's not an ideal situation, but it in no way indicates a complete erosion of the first amendment.
And those kids were looking for a fight. Even the editor of the video is unethically juxtaposing text to communicate agenda. When the SWAT guy moved his hand our of sight, the text read "reaching for his taser", which he wasn't doing. Inserting this text reminds people of the "don't tase me, bro" incident from months back. It's a complete pathos appeal and only weakens an argument. This video is amateur at best and proves nothing at all. It has an agenda and seeks to illusion. I mean, you must see this. Look at it objectively.
That was the National Mall. If anyone could congregate there freely at all times, it would be chaos. I remember some twenty years ago when the National Socialist Neo-nazi's tried to protest there without a permit, and of course, were turned away. It's probably a necessary law in that area.