Historically, the three arrows symbol has been used by groups attacking Socialists, hence why I added the slash. Overwhelmingly, those who use the three arrows, including those who originated the symbol, are Social Democrats. Social Democracy is not Socialism, it's Capitalism with larger and more robust safety nets, and as such said Social Democrats have historically had just as much problem with Socialists as they have with Communists.

This is without getting into my own personal analysis of Socialism, that being that any society dedicated to maintaining Socialism will almost certainly eventually move towards Commnism anyways. This is just historical contextualization. Three Arrows the YouTuber identifies as a Social Democrat as well, so this is again reinforcing the idea that I don't think someone who isn't a Socialist and doesn't support Socialism should be seen as an authority on analyzing whether or not a system is Socialist.

That's why I recommended a historian with a doctorate who wrote a famous book on precisely this subject. It's a quick, snappy read too.