What do you mean by actually played them? I have actually played them of course why I can comment on the matter.
You are full of hyperbole. Ask every one of the commentators here whether Horizon is arcade or sim. You'll be shocked.
Also you haven't given one concrete and well thought out opinion on why Horizon is simcade. No, segregation of cars into categories does not make a game realistic. Its not what draws people to simulation games. GT6 doesn't even have car classes per se. So is that less of a sim than Horizon 3? Lmao.
I already named numerous features and options that make the Horizon games closer to being simcades then pure arcade racers. But I guess you don't have a clue on what makes a pure arcade racer.