Bears, and Twinks, and others? Oh My!

Why is it that when you say, "I am not into bears or chubs" guys take that to mean, "I am therefore ONLY interested in twinks". As if there are not other guys in between. My ex, who I met when he was 29 and I was 34, is still hot, very hot (at 42) and he clearly isn't a 'twink'. He just isn't a chunky, hairy guy, with a bad goatee, who looks 10 years older than he is.