There have been 800+ cases in the UK alone of YPG volunteers. There was an attempt at one point by the right to label them as terrorists and attempt to prosecute them on return to the UK. This was largely defeated.

We have an extremely small muslim population. In countries with larger muslim populations these numbers are definitely higher. I don't think 10k+ is an unfair estimate, especially given that the Spanish Civil War had a documented 30k foreign volunteers from Europe. Leftist volunteers travelling out on our continent is not at all uncommon, we are internationalists and these battles are as important as the battles at home.

One extremely interesting and relevant aspect of these groups is that they are pathways to radicalising America troops.

US officials declared their opposition. “We don’t support self-rule, semi-autonomous zones inside Syria,” State Department spokesperson John Kirby said. “We just don’t.”

A few months later, US officials took more concrete action. After seeing reports that US special forces were wearing patches with the YPG insignia — a sign of the growing solidarity between American and Kurdish military forces — officials ordered the special-operation forces to remove them.

We can effectively reach people that matter internationally through these methods. The US troops see those of us that are out there and deeply empathise with us when they're not under orders to kill us.