The gratuitous mention that a 'Zionist' [sic] condemned the attack, and the implication that it is something unusual. In actual fact the German Jewish community tends to be very outspoken about stuff like this - for some strange reason they feel strongly about neo-Nazis.

That's followed by vague insinuations that shadowy forces are behind the skinheads.  When someone with antisemitic opinions brings up Jews in connection with something where it isn't particularly relevant, then starts making weird suggestions about how there are secret forces behind the phenomenon under discussion then it is pretty clear what he is thinking.

I suppose I should do some background research on all posters before responding to them in the future?

No reason to do that. Fortunately racists are far and few between on this site, and one can generally assume that posters are not racist unless proven otherwise. In this case it is pretty clear (see the comment I posted right around the time you posted yours)