Is there some actual concern about WireGuard itself or just the FreeBSD implementation?
That is not true. Everyone acknowledges the code is not up to the required standard so it is being removed but Kyle and others will continue to work on it with the aim of adding it back.
Edit: as @asmr below linked to, he has has since announced that he is quitting.
[1] https://lists.zx2c4.com/pipermail/wireguard/2021-March/00650...