You need to learn your Internet history. It wasn't so long ago that we had a diverse, interoperable community of instant messaging platforms based on XMPP, an open, federated protocol. Anybody could host their own XMPP server, and communicate with any other XMPP server. Then in 2006, Google added XMPP support to their Talk app and integrated it into the Gmail web interface. But there were problems:

First of all, despites collaborating to develop the XMPP standard, Google was doing its own closed implementation that nobody could review. It turns out they were not always respecting the protocol they were developing. They were not implementing everything. This forced XMPP development to be slowed down, to adapt. Nice new features were not implemented or not used in XMPP clients because they were not compatible with Google Talk (avatars took an awful long time to come to XMPP). Federation was sometimes broken: for hours or days, there would not be communications possible between Google and regular XMPP servers. The XMPP community became watchers and debuggers of Google’s servers, posting irregularities and downtime (I did it several times, which is probably what prompted the job offer).

And because there were far more Google talk users than "true XMPP" users, there was little room for "not caring about Google talk users". Newcomers discovering XMPP and not being Google talk users themselves had very frustrating experience because most of their contact were Google Talk users. They thought they could communicate easily with them but it was basically a degraded version of what they had while using Google talk itself. A typical XMPP roster was mainly composed of Google Talk users with a few geeks.

Only a few years later, Google would discontinue Google Talk, migrated all their users to Hangouts, and decimated the XMPP community in an instant. Most of the Google users never noticed, outside of some invalid contacts in their list.

That's why everyone distrusts Meta. Even with Threads being a relatively unsuccessful platform by commercial social media standards, its active userbase still dwarfs the entire Fediverse combined. There's absolutely nothing stopping Meta from running the exact same playbook:

• Add ActivityPub support, but only partially

• Add new features to ActivityPub without consulting with the rest of the Fediverse or documenting the extensions, degrading the experience for everyone not using Threads

• Entice Fediverse users to migrate to Threads--after all, why use Mastodon or Lemmy when 95%+ of ActivityPub traffic originates from Threads?

• Deprecate ActivityPub support after most of the Fediverse is on Threads, leaving it smaller and more fragmented than if Threads had never federated at all, while forcing everyone who migrated from another Fediverse platform to Threads into an impossible choice between abandoning the vast majority of their contacts or subjecting themselves to Meta's policies, tracking, and moderation