Not true at all. We do use the "Source First" license for a lot of things, but all of my projects are OSI Certified (TM) Open Source. For example:

* https://github.com/futo-org/circles-android (AGPL)

* https://github.com/futo-org/circles-ios (AGPL)

* https://github.com/futo-org/matrix.swift (Apache 2.0)

There are a few other little things here and there, mostly Apache 2.0, but the above are the bigger ones.

Edit: There is also Alex's Whisper finetuning repo https://github.com/futo-org/whisper-acft (MIT)