drivechains add a hash and a counter to the block header. it lets people, if they want to, put their coins in an address controlled by the miners. those bitcoin then can move around on a sidechain. it's like the liquid federation or the wbtc multisig but the miners are the custodians.

non-technical people and people that have delusions that bitcoin can scale by some, as yet undiscovered, magic crypto shared utxo thing (or dumber people that think bitcoin can scale just with lightning) are upset because they see a growing movement to activate drivechains and they don't get it