You posted in a general travel subforum. If you want to complain about SQ, then I suggest you complain in the subforum here. But if you're making a general observation, as I said, not everyone uses (or trusts) Whatsapp. In Taiway/Japan, Line is likely more popular. Also it depends on where you go and how travel savvy you are. For example. If I were to go to Singapore, I'd be picking up a tourist sim from one of the providers (eg, Singtel's Hi Card). That would provide me with voice and data function. If I know I'm going to visit Taipei, I'd be picking up a local card from there that would provide me with voice/data.

Failing either, I'd do some research pre-travel to identify known public hotspots (like cafes or other stores) that would allow me to connect and make calls if I need to.

Airlines (especially now) have limited resources and will focus those resources as their markets dictate. So for SQ, they would have a team for twitter (like a media team) and a CS team for whatsapp). For EVA, it might be line.... for BA, they're more likely multi-region phone centers with a media team for Twitter/FB. Again, it depends on their customer base. Demanding for them to cover all bases is unreasonable and asking for a higher cost to be inflicted on you and other travellers.