Because the nature of the base product being open source is that the VSCodium devs can patch out any sufficiently bad behaviour, and the risk of this becoming a fork should serve to discourage this behaviour in the first place.
But there’s open source and there’s open source right? I mean theoretically anyone can fork Android, but Google has created a lot of hurdles for actually making one a success.
I think there’s always a risk that a product like this can be set up in such a way that OSS is used mainly as an advertising feature, and essential features can be gradually moved from the open source section to proprietary code.
All I’m saying is that open source is not a panacea, and there are plenty of ways for large well resourced entities to abuse it