I would welcome open source code for all the software that we allow to run on our devices, but let’s not pretend they’re all equivalent. It’s likely that sensible reason lies behind the focus on TikTok and a few other specific companies. Probably related:

https://gizmodo.com/ahead-of-scotus-hearing-study-finds-tiktok-is-likely-vehicle-for-chinese-propaganda-2000546312