I lived in Minnesota for 30 years, and can tell you that's completely bullshit. Your tires have far more to do with safety on icy roads than your transmission.
I drive tractor trailers for a living and drive manual while living in Canada, downshifting is very good for preventing slipping and sliding in situations where you need to slow down. Tires are very important, but being able to down shift and slow down with a more natural feeling will prevent you from sliding as well.
Did you know that you can downshift an automatic transmission, too?
If you have a tiptronic transmission, sure. Most automatics on the road dont have that.
Literally every automatic transmission has a stick to go down into at least two lower gears, bruh.
Which is not actually the same due to how a torque converter works compared to how a clutch works.
People who don't know shit about cars arguing about cars is hilarious. ---
Suck less, Rock Moar Have I licked butt hole before? All the time. --r4xor