I can believe tectonic effects would effect the area under Lake Mead, as at 35 km^3, it adds a whopping 35 billion tonnes of weight of water. I had heard about those microquakes too.
The Konya Dam reservoir too, might have had an impact, despite its smaller volume of 2.76 km^3, since it is in a particulary tectonically stressed area. (Although I do not see how to establish causation -- given the tectonics of the region, that earthquake would have eventually happened with or without the reservoir. Did the reservoir cause the earthquake to happen earlier than it would have happened otherwise? There's no way to know.)
But Taipei 101? It weighs one-fortieth of one percent of the Konya Dam reservoir, which was already on the small side of what is physically plausible to have an effect.
The 'pressure' arguement is just ridiculous, as that full additional pressure only exists right at the surface ground level. At a depth where the additional pressure might have an impact on the tectonics (several km), that 700,000 tonnes is spread over several square km, for an additional pressure increment of around 165 kg per square metre (By way of comparison, a single 50mm rainfall event adds 50 kg per square metre over the entire rainfall area. Taipei regularly is hit by typhoons that dump up to 1200mm of rain.)