A couple things to note here. The FCC has only spectrum licensing and spectrum use jurisdiction, not import jurisdiction. Thus, this "ban" is likely to fall apart in court.
Second, the "ban" is on "consumer-grade" routers, which means 1) all APs, switches, and enterprise routers aren't impacted 2) it would render consumer routers insanely expensive if followed through on. Unless, of course, you're using Starlink, who this "ban" seems to have been tailored to benefit.
In short, this isn't about cybersecurity, it's straight up cronyism.