(There's also no one modern group using the Three Arrows. It's a general symbol of the left, like the wildcat or the "A." It's not even clear who they'd be a "hate group" against.)
> The SDP was and is a center-left party. You can look their platform up today, and confirm that it is neither historically nor currently hateful.
Words don't have any meaning anymore, so they mean whatever someone wants them to mean, so everything is true.
Also, various symbols associated to the GOP were observed in the context of the January 6th incident. So are these all hate symbols? Certainly not and every such notion is utter nonsense. Attributing meaning by incidental association is not how it works.
Historically, the three-arrows symbol emerged in 1932 as a symbol of resistance against the NSDAP and was adopted as the official symbol of the German social-democratic party (SPD) that same year. It symbolises an equidistance from the NSDAP, the communist KPD, and monarchism. In this context, it was decried as a symbol of a "social fascist terror organisation" by the KPD, while conservative parties hedged fears of a people's front at that very same time. It was also adopted by social-democrats in other countries, e.g. by the SPÖ in Austria (also 1932).
Wikipedia cites a slogan "neither Stalin's slaves nor Hitler's henchmen" in the context of this symbol. This is as much "hate" as you may get from this.
https://en.wikipedia.org/wiki/Three_Arrows
BTW, the social-democrat three-arrows symbol is three parallel arrows pointing downwards left inside a circle, while the Three Arrows Capital logo is three arrows fanning out and pointing to the upper right, intersected by a quadrant of a circle. Where the former is blocky and in uniform color (most often white on red), the latter is multicolored and drawn in fine lines. The two symbols have about nothing in common.