This article seems a little inaccurate to me, or at least incomplete.
On phobias, it's not quite as simple as a 'fear memory', although certainly a part of it when we're discussing 'conditioned fear' (e.g. PTSD). There's a part of your brain called the amygdala that is implicated in modulation of memory formation and emotional processing. It's part of the limbic system, which is tied in to the body's autonomic nervous system. This controls your 'fight or flight' response, essentially a sudden release of adrenaline into your system which causes 'anxiety symptoms': increased heart rate, increased perspiration, butterflies in stomach (due to diversion of blood flow to large muscles in your limbs).
The amygdala is sort of like a 'heuristic co-processor' that receives sensory input earlier than other parts of the brain. If the input matches a heuristic, the body's fight or flight response is activated. If the amygdala is dysfunctional, is 'pre-programmed' with heuristics now considered maladaptive, or you've had experiences that have 'programmed' inappropriate heuristics, it will activate your fight or flight response in response to non-threatening stimuli.
Drugs like propranolol, which I take daily for a panic disorder, antagonise (i.e. block) beta-adrendergic receptors, blocking the action of adrenaline and noradrenaline, which dampens the fight or flight response. This reduces or eliminates panic/anxiety like symptoms, and alters how memories are encoded while under its effects (however I'm not clear on whether this interferes with memory formation, or whether it causes the memories to be encoded in a different way).
The part I find most interesting is the 'pre-programmed maladaptive heuristics' still present in our heuristic database. Evolution is a slow process, and has not caught up to our rapidly changing context. For instance, if you've ever given a public speech, you've probably experienced a 'fight-or-flight' response. It's not because you've had some bad past experience with public speaking that has conditioned a 'fear response'; it's because of a left over heuristic in your amygdala that may have been adaptive a thousands of years ago.
Humans used to live in small tribes or groups with maybe a dozen other humans, and the only other humans they might have contact with in their life would be when fighting other groups for resources. If you publicly humiliated yourself in this context, it would have likely meant elimination from the gene pool or possibly even death. In a modern context, where you're giving a speech to a room full of people in another country, this isn't even mildly the case. But evolution is a slow process, so many of us still experience a fight or flight response anyway, which is maladaptive.