Why are WR in the slot covered by non-CBs in American football?

The slot is the area between the last offensive lineman on the line and the wide receiver that is split out to that end of the field

Fantasy football wide receiver draft guide: Every starter, slot WR for 2023

what is a slot reciever From the slot standpoint, in zone coverage, a linebacker will usually walk out and kind of be head-up over you, if you're a slot receiver, and

what is the best time to play the slot machines selected Josh Downs in the third round of the 2023 NFL Draft, bringing two players with experience in the slot to Shane Steichen's offense