It makes it easier to not offer functionality in Europe. Because to offer the functionality in Europe you have to do the extra work of making sure any competitor who could go crying to the euro officials can plausibly inject a competing thing with equal integration.
They pride themselves as being privacy and security minded when releasing new products.
They already have mechanisms to trust some accessories and apps ("my watch" vs. "your watch"). Just offer the same to devices not made by them.
If the user then decides to install the (probably illegal) "Meta Spy Master 9000 App" then so be it.
They are adults after all.
The DMA very explicitly disagrees with the notion of "Apple knows best" and until the tech giants come to terms with that, their comments on the laws cannot be trusted.
I would love to see them cooperate because then, over time, their considerable technical knowledge could be used to work out the details.