I read some of the mailing list drama about Speck. Linus no doubt let this pass because Google will be a major influence in the Linux Foundation, indirectly paying his salary.

https://itsfoss.com/nsas-encryption-algorithm-in-linux-kernel-is-creating-unease-in-the-community

This is the advantage of FOSS. The NSA can bribe engineers, but distro makers or end users can still remove the offending code if they're aware of it.