I just sincerely hope that CX and KA start to look into their fuel policy and chose a maybe slightly more conservative (and given the event described above) a safer alternate. Just like many other airlines do.
CX Line Ops keeps a close eye on the weather patterns around Hong Kong and if the forecast is marginal they would normally plan a more distant alternate such as Kaohsiung or Taipei rather than Macau. At the very least the CFP would call for extra holding fuel, which is not subject to payload. The captain also has the discretion to take more fuel if he or she thinks it is necessary, and unlike some airlines, CX does not normally question the captain's decision.
Holding Taipei as an alternate on an ULH flight imposes a significant payload penalty as it requires an uplift of at least an extra 9-10 tonnes of fuel. If CX did that on every single flight regardless of the weather forecast, they would forgo a huge amount of revenue. Consequently, if the weather forecast is good they would normally plan a closer alternate such as Macau or Shenzen.
CX has been operating out of Hong Kong for a long time and they are very familiar with the peculiarities of the weather and airspace, etc. Nothing's ever perfect, but Line Ops are pretty good at adding extra fuel to CFPs when they think it is necessary.