Each of language groups across the globe has its own dominant and different messaging apps. US has Messenger, Korea has KakaoTalk, Japan took LINE, China built WeChat, Russia picked Telegram, and so on. The Meta Facebook/Messenger/Instagram triad isn't the global default of social apps the way it might look to people from US.
And I don't think it takes conspiracy theories to explain it, maybe users don't like platforms that isn't dominated by similar users of their primary language, or maybe there are something else that prevent app experiences optimized for two distinct cultures at the same time.
This isn't really true. WhatsApp was used pre-acquisition and continues to be dominant throughout LATAM, Africa, and Europe in addition to US/NA. Only in the APJC region and Russia do we see significant divergence in messaging apps.
Having traveled extensively in these places, I always theorized it was due to UX behavior aligning well with the local languages. While the countries WhatsApp dominates speak different languages, they all use the Latin alphabet. In Russia and APJC there are many non-Latin alphabets used and those languages may also use different directions for writing/reading than Romance and Germanic languages.
One advantage of Telegram over WhatsApp is that you don't have to display your phone number to your contacts and random people in group chats and blogs.
With some amusing exceptions: doctors are exclusively on WhatsApp; older (60+) people are often only on WhatsApp (and pre-Microsoft Skype before that).
LINE is very popular in Thailand for unclear reasons, I've heard the theory that their cute sticker packs set them apart in the early days. In the rest of SEA Whatsapp is the most popular.
