Camille Grammer RIPS Kelsey Over Car Seat Drama -- 'Extremely Irresponsible'

Camille Grammer tore into her ex-husband Kelsey Grammer last night -- calling him "extremely irresponsible" for loading his 4-month-old daughter into an SUV without a car seat.

Camille and some friends were hitting up a party at Kyle Richards' boutique "KYLE" in Bev Hills last night ... when she blasted her ex.

"I don't think it's good to have a 4-month-old in a car without a car seat ... it's so irresponsible."

Kelsey's rep has since released the following laughable statement about the incident:

"Kelsey went back in and got the car seat and met them at the car. Did the car drive a few yards without the car seat? Yes. At no time does the video show them leaving the airport with the baby not in the car seat."

Of course, the video shows the car merging into airport traffic ... we know they met Kelsey at baggage claim, on a different level, which means they had to loop around LAX -- and that trip is way more than "a few yards" ... still illegal ... and very dangerous. By the way, we're told they could have been driving for at least 10 minutes before hooking up with Kelsey.