It's been a while since I have seen the video but i do remember the context behind it. It was during the 2020 BLM protests in the United States and many were identifying themselves as antifa (take it with a grain of salt, antifa is merely an ideology with no real leader or representative).

Some of those identifying as antifa were starting fights with others and making accusations. This was in addition to general arson ranging from property theft, destruction of property and starting fires. There are some even lighting up fireworks in the streets but it's hard to tell if they are "apart" of antifa.

A Tankie is a hardcore communist usually with an affinity for authoritarianism. They are named "tankies" because during the cold war communists in western countries were defending the USSR's use of tanks to crush anti government/communist protest, thus the name Tankie.

While one doesn't mean the other they often have a prominent overlap with many of antifa being Tankies and vice versa.

Edit: the confusion was the original comment mistook the antifa logo as a communist symbol and referred to them as such and my comment was referring to antifa specifically .